-@\input texinfo @c -*-texinfo-*-
+\input texinfo @c -*-texinfo-*-
@setfilename gcj.info
@settitle Guide to GNU gcj
+@c Merge the standard indexes into a single one.
+@syncodeindex fn cp
+@syncodeindex vr cp
+@syncodeindex ky cp
+@syncodeindex pg cp
+@syncodeindex tp cp
+
+@include gcc-common.texi
+
@c Note: When reading this manual you'll find lots of strange
@c circumlocutions like ``compiler for the Java language''.
@c This is necessary due to Sun's restrictions on the use of
@c the word ``Java'.
@c When this manual is copyrighted.
-@set copyrights-gcj 2001
-
-@c Versions
-@set version-gcc 3.1
-@set which-gcj GCC-@value{version-gcc}
-
-@ifinfo
-@format
-@dircategory Programming
-@direntry
-* Gcj: (gcj). Ahead-of-time compiler for the Java language
-@end direntry
+@set copyrights-gcj 2001, 2002, 2003, 2004, 2005, 2006, 2007
-@dircategory Individual utilities
-@direntry
-* gcjh: (gcj)Invoking gcjh.
- Generate header files from Java class files
-* jv-scan: (gcj)Invoking jv-scan.
- Print information about Java source files
-* jcf-dump: (gcj)Invoking jcf-dump.
- Print information about Java class files
-* gij: (gcj)Invoking gij. GNU interpreter for Java bytecode
-@end direntry
-@end format
-
-Copyright (C) @value{copyrights-gcj} Free Software Foundation, Inc.
+@copying
+@c man begin COPYRIGHT
+Copyright @copyright{} @value{copyrights-gcj} Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
+under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with the
Invariant Sections being ``GNU General Public License'', the Front-Cover
texts being (a) (see below), and with the Back-Cover Texts being (b)
-(see below). A copy of the license is included in the section entitled
+(see below). A copy of the license is included in the
+@c man end
+section entitled
``GNU Free Documentation License''.
+@ignore
+@c man begin COPYRIGHT
+man page gfdl(7).
+@c man end
+@end ignore
+
+@c man begin COPYRIGHT
(a) The FSF's Front-Cover Text is:
You have freedom to copy and modify this GNU Manual, like GNU
software. Copies published by the Free Software Foundation raise
funds for GNU development.
+@c man end
+@end copying
+
+@ifinfo
+@format
+@dircategory Software development
+@direntry
+* Gcj: (gcj). Ahead-of-time compiler for the Java language
+@end direntry
+
+@dircategory Individual utilities
+@direntry
+* jcf-dump: (gcj)Invoking jcf-dump.
+ Print information about Java class files
+* gij: (gcj)Invoking gij. GNU interpreter for Java bytecode
+* gcj-dbtool: (gcj)Invoking gcj-dbtool.
+ Tool for manipulating class file databases.
+* jv-convert: (gcj)Invoking jv-convert.
+ Convert file from one encoding to another
+* grmic: (gcj)Invoking grmic.
+ Generate stubs for Remote Method Invocation.
+* gc-analyze: (gcj)Invoking gc-analyze.
+ Analyze Garbage Collector (GC) memory dumps.
+@end direntry
+@end format
+
+@insertcopying
@end ifinfo
@titlepage
@title GNU gcj
+@versionsubtitle
@author Tom Tromey
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} @value{copyrights-gcj} Free Software Foundation, Inc.
-@sp 2
-For the @value{which-gcj} Version*
-@sp 1
Published by the Free Software Foundation @*
-59 Temple Place - Suite 330@*
-Boston, MA 02111-1307, USA@*
+51 Franklin Street, Fifth Floor@*
+Boston, MA 02110-1301, USA@*
@sp 1
-Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
-any later version published by the Free Software Foundation; with the
-Invariant Sections being ``GNU General Public License'', the Front-Cover
-texts being (a) (see below), and with the Back-Cover Texts being (b)
-(see below). A copy of the license is included in the section entitled
-``GNU Free Documentation License''.
-
-(a) The FSF's Front-Cover Text is:
-
- A GNU Manual
-
-(b) The FSF's Back-Cover Text is:
-
- You have freedom to copy and modify this GNU Manual, like GNU
- software. Copies published by the Free Software Foundation raise
- funds for GNU development.
+@insertcopying
@end titlepage
@contents
@page
@node Top
@top Introduction
-This manual describes how to use @code{gcj}, the GNU compiler for the
-Java programming language. @code{gcj} can generate both @file{.class}
+This manual describes how to use @command{gcj}, the GNU compiler for the
+Java programming language. @command{gcj} can generate both @file{.class}
files and object files, and it can read both Java source code and
@file{.class} files.
@menu
-* Copying:: The GNU General Public License
+* Copying:: The GNU General Public License
* GNU Free Documentation License::
How you can share and copy this manual
-* Invoking gcj:: Compiler options supported by @code{gcj}
+* Invoking gcj:: Compiler options supported by @command{gcj}
* Compatibility:: Compatibility between gcj and other tools for Java
-* Invoking gcjh:: Generate header files from class files
-* Invoking jv-scan:: Print information about source files
* Invoking jcf-dump:: Print information about class files
* Invoking gij:: Interpreting Java bytecodes
+* Invoking gcj-dbtool:: Tool for manipulating class file databases.
+* Invoking jv-convert:: Converting from one encoding to another
+* Invoking grmic:: Generate stubs for Remote Method Invocation.
+* Invoking gc-analyze:: Analyze Garbage Collector (GC) memory dumps.
+* About CNI:: Description of the Compiled Native Interface
+* System properties:: Modifying runtime behavior of the libgcj library
* Resources:: Where to look for more information
+* Index:: Index.
@end menu
-@node Copying
-@unnumbered GNU GENERAL PUBLIC LICENSE
-@center Version 2, June 1991
-
-@display
-Copyright @copyright{} 1989, 1991 Free Software Foundation, Inc.
-59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
-
-Everyone is permitted to copy and distribute verbatim copies
-of this license document, but changing it is not allowed.
-@end display
-
-@unnumberedsec Preamble
-
- The licenses for most software are designed to take away your
-freedom to share and change it. By contrast, the GNU General Public
-License is intended to guarantee your freedom to share and change free
-software---to make sure the software is free for all its users. This
-General Public License applies to most of the Free Software
-Foundation's software and to any other program whose authors commit to
-using it. (Some other Free Software Foundation software is covered by
-the GNU Library General Public License instead.) You can apply it to
-your programs, too.
-
- When we speak of free software, we are referring to freedom, not
-price. Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-this service if you wish), that you receive source code or can get it
-if you want it, that you can change the software or use pieces of it
-in new free programs; and that you know you can do these things.
-
- To protect your rights, we need to make restrictions that forbid
-anyone to deny you these rights or to ask you to surrender the rights.
-These restrictions translate to certain responsibilities for you if you
-distribute copies of the software, or if you modify it.
-
- For example, if you distribute copies of such a program, whether
-gratis or for a fee, you must give the recipients all the rights that
-you have. You must make sure that they, too, receive or can get the
-source code. And you must show them these terms so they know their
-rights.
-
- We protect your rights with two steps: (1) copyright the software, and
-(2) offer you this license which gives you legal permission to copy,
-distribute and/or modify the software.
-
- Also, for each author's protection and ours, we want to make certain
-that everyone understands that there is no warranty for this free
-software. If the software is modified by someone else and passed on, we
-want its recipients to know that what they have is not the original, so
-that any problems introduced by others will not reflect on the original
-authors' reputations.
-
- Finally, any free program is threatened constantly by software
-patents. We wish to avoid the danger that redistributors of a free
-program will individually obtain patent licenses, in effect making the
-program proprietary. To prevent this, we have made it clear that any
-patent must be licensed for everyone's free use or not licensed at all.
-
- The precise terms and conditions for copying, distribution and
-modification follow.
-
-@iftex
-@unnumberedsec TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-@end iftex
-@ifinfo
-@center TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
-@end ifinfo
-
-@enumerate 0
-@item
-This License applies to any program or other work which contains
-a notice placed by the copyright holder saying it may be distributed
-under the terms of this General Public License. The ``Program'', below,
-refers to any such program or work, and a ``work based on the Program''
-means either the Program or any derivative work under copyright law:
-that is to say, a work containing the Program or a portion of it,
-either verbatim or with modifications and/or translated into another
-language. (Hereinafter, translation is included without limitation in
-the term ``modification''.) Each licensee is addressed as ``you''.
-
-Activities other than copying, distribution and modification are not
-covered by this License; they are outside its scope. The act of
-running the Program is not restricted, and the output from the Program
-is covered only if its contents constitute a work based on the
-Program (independent of having been made by running the Program).
-Whether that is true depends on what the Program does.
-
-@item
-You may copy and distribute verbatim copies of the Program's
-source code as you receive it, in any medium, provided that you
-conspicuously and appropriately publish on each copy an appropriate
-copyright notice and disclaimer of warranty; keep intact all the
-notices that refer to this License and to the absence of any warranty;
-and give any other recipients of the Program a copy of this License
-along with the Program.
-
-You may charge a fee for the physical act of transferring a copy, and
-you may at your option offer warranty protection in exchange for a fee.
-
-@item
-You may modify your copy or copies of the Program or any portion
-of it, thus forming a work based on the Program, and copy and
-distribute such modifications or work under the terms of Section 1
-above, provided that you also meet all of these conditions:
-
-@enumerate a
-@item
-You must cause the modified files to carry prominent notices
-stating that you changed the files and the date of any change.
-
-@item
-You must cause any work that you distribute or publish, that in
-whole or in part contains or is derived from the Program or any
-part thereof, to be licensed as a whole at no charge to all third
-parties under the terms of this License.
-
-@item
-If the modified program normally reads commands interactively
-when run, you must cause it, when started running for such
-interactive use in the most ordinary way, to print or display an
-announcement including an appropriate copyright notice and a
-notice that there is no warranty (or else, saying that you provide
-a warranty) and that users may redistribute the program under
-these conditions, and telling the user how to view a copy of this
-License. (Exception: if the Program itself is interactive but
-does not normally print such an announcement, your work based on
-the Program is not required to print an announcement.)
-@end enumerate
-
-These requirements apply to the modified work as a whole. If
-identifiable sections of that work are not derived from the Program,
-and can be reasonably considered independent and separate works in
-themselves, then this License, and its terms, do not apply to those
-sections when you distribute them as separate works. But when you
-distribute the same sections as part of a whole which is a work based
-on the Program, the distribution of the whole must be on the terms of
-this License, whose permissions for other licensees extend to the
-entire whole, and thus to each and every part regardless of who wrote it.
-
-Thus, it is not the intent of this section to claim rights or contest
-your rights to work written entirely by you; rather, the intent is to
-exercise the right to control the distribution of derivative or
-collective works based on the Program.
-
-In addition, mere aggregation of another work not based on the Program
-with the Program (or with a work based on the Program) on a volume of
-a storage or distribution medium does not bring the other work under
-the scope of this License.
-
-@item
-You may copy and distribute the Program (or a work based on it,
-under Section 2) in object code or executable form under the terms of
-Sections 1 and 2 above provided that you also do one of the following:
-
-@enumerate a
-@item
-Accompany it with the complete corresponding machine-readable
-source code, which must be distributed under the terms of Sections
-1 and 2 above on a medium customarily used for software interchange; or,
-
-@item
-Accompany it with a written offer, valid for at least three
-years, to give any third party, for a charge no more than your
-cost of physically performing source distribution, a complete
-machine-readable copy of the corresponding source code, to be
-distributed under the terms of Sections 1 and 2 above on a medium
-customarily used for software interchange; or,
-
-@item
-Accompany it with the information you received as to the offer
-to distribute corresponding source code. (This alternative is
-allowed only for noncommercial distribution and only if you
-received the program in object code or executable form with such
-an offer, in accord with Subsection b above.)
-@end enumerate
-
-The source code for a work means the preferred form of the work for
-making modifications to it. For an executable work, complete source
-code means all the source code for all modules it contains, plus any
-associated interface definition files, plus the scripts used to
-control compilation and installation of the executable. However, as a
-special exception, the source code distributed need not include
-anything that is normally distributed (in either source or binary
-form) with the major components (compiler, kernel, and so on) of the
-operating system on which the executable runs, unless that component
-itself accompanies the executable.
-
-If distribution of executable or object code is made by offering
-access to copy from a designated place, then offering equivalent
-access to copy the source code from the same place counts as
-distribution of the source code, even though third parties are not
-compelled to copy the source along with the object code.
-
-@item
-You may not copy, modify, sublicense, or distribute the Program
-except as expressly provided under this License. Any attempt
-otherwise to copy, modify, sublicense or distribute the Program is
-void, and will automatically terminate your rights under this License.
-However, parties who have received copies, or rights, from you under
-this License will not have their licenses terminated so long as such
-parties remain in full compliance.
-
-@item
-You are not required to accept this License, since you have not
-signed it. However, nothing else grants you permission to modify or
-distribute the Program or its derivative works. These actions are
-prohibited by law if you do not accept this License. Therefore, by
-modifying or distributing the Program (or any work based on the
-Program), you indicate your acceptance of this License to do so, and
-all its terms and conditions for copying, distributing or modifying
-the Program or works based on it.
-
-@item
-Each time you redistribute the Program (or any work based on the
-Program), the recipient automatically receives a license from the
-original licensor to copy, distribute or modify the Program subject to
-these terms and conditions. You may not impose any further
-restrictions on the recipients' exercise of the rights granted herein.
-You are not responsible for enforcing compliance by third parties to
-this License.
-
-@item
-If, as a consequence of a court judgment or allegation of patent
-infringement or for any other reason (not limited to patent issues),
-conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License. If you cannot
-distribute so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you
-may not distribute the Program at all. For example, if a patent
-license would not permit royalty-free redistribution of the Program by
-all those who receive copies directly or indirectly through you, then
-the only way you could satisfy both it and this License would be to
-refrain entirely from distribution of the Program.
-
-If any portion of this section is held invalid or unenforceable under
-any particular circumstance, the balance of the section is intended to
-apply and the section as a whole is intended to apply in other
-circumstances.
-
-It is not the purpose of this section to induce you to infringe any
-patents or other property right claims or to contest validity of any
-such claims; this section has the sole purpose of protecting the
-integrity of the free software distribution system, which is
-implemented by public license practices. Many people have made
-generous contributions to the wide range of software distributed
-through that system in reliance on consistent application of that
-system; it is up to the author/donor to decide if he or she is willing
-to distribute software through any other system and a licensee cannot
-impose that choice.
-
-This section is intended to make thoroughly clear what is believed to
-be a consequence of the rest of this License.
-
-@item
-If the distribution and/or use of the Program is restricted in
-certain countries either by patents or by copyrighted interfaces, the
-original copyright holder who places the Program under this License
-may add an explicit geographical distribution limitation excluding
-those countries, so that distribution is permitted only in or among
-countries not thus excluded. In such case, this License incorporates
-the limitation as if written in the body of this License.
-
-@item
-The Free Software Foundation may publish revised and/or new versions
-of the General Public License from time to time. Such new versions will
-be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-Each version is given a distinguishing version number. If the Program
-specifies a version number of this License which applies to it and ``any
-later version'', you have the option of following the terms and conditions
-either of that version or of any later version published by the Free
-Software Foundation. If the Program does not specify a version number of
-this License, you may choose any version ever published by the Free Software
-Foundation.
-
-@item
-If you wish to incorporate parts of the Program into other free
-programs whose distribution conditions are different, write to the author
-to ask for permission. For software which is copyrighted by the Free
-Software Foundation, write to the Free Software Foundation; we sometimes
-make exceptions for this. Our decision will be guided by the two goals
-of preserving the free status of all derivatives of our free software and
-of promoting the sharing and reuse of software generally.
-
-@iftex
-@heading NO WARRANTY
-@end iftex
-@ifinfo
-@center NO WARRANTY
-@end ifinfo
-
-@item
-BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
-FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN
-OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
-PROVIDE THE PROGRAM ``AS IS'' WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
-OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
-MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS
-TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE
-PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
-REPAIR OR CORRECTION.
-
-@item
-IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
-REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
-INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
-OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
-TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
-YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
-PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
-POSSIBILITY OF SUCH DAMAGES.
-@end enumerate
-
-@iftex
-@heading END OF TERMS AND CONDITIONS
-@end iftex
-@ifinfo
-@center END OF TERMS AND CONDITIONS
-@end ifinfo
-
-@page
-@unnumberedsec How to Apply These Terms to Your New Programs
-
- If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
- To do so, attach the following notices to the program. It is safest
-to attach them to the start of each source file to most effectively
-convey the exclusion of warranty; and each file should have at least
-the ``copyright'' line and a pointer to where the full notice is found.
-
-@smallexample
-@var{one line to give the program's name and a brief idea of what it does.}
-Copyright (C) @var{year} @var{name of author}
-
-This program is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program; if not, write to the Free Software
-Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
-@end smallexample
-
-Also add information on how to contact you by electronic and paper mail.
-
-If the program is interactive, make it output a short notice like this
-when it starts in an interactive mode:
-
-@smallexample
-Gnomovision version 69, Copyright (C) @var{year} @var{name of author}
-Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
-type `show w'.
-This is free software, and you are welcome to redistribute it
-under certain conditions; type `show c' for details.
-@end smallexample
-
-The hypothetical commands @samp{show w} and @samp{show c} should show
-the appropriate parts of the General Public License. Of course, the
-commands you use may be called something other than @samp{show w} and
-@samp{show c}; they could even be mouse-clicks or menu items---whatever
-suits your program.
-
-You should also get your employer (if you work as a programmer) or your
-school, if any, to sign a ``copyright disclaimer'' for the program, if
-necessary. Here is a sample; alter the names:
-
-@smallexample
-Yoyodyne, Inc., hereby disclaims all copyright interest in the program
-`Gnomovision' (which makes passes at compilers) written by James Hacker.
-
-@var{signature of Ty Coon}, 1 April 1989
-Ty Coon, President of Vice
-@end smallexample
-
-This General Public License does not permit incorporating your program into
-proprietary programs. If your program is a subroutine library, you may
-consider it more useful to permit linking proprietary applications with the
-library. If this is what you want to do, use the GNU Library General
-Public License instead of this License.
-
+@include gpl_v3.texi
@include fdl.texi
@node Invoking gcj
@chapter Invoking gcj
-As @code{gcj} is just another front end to @code{gcc}, it supports many
+@c man title gcj Ahead-of-time compiler for the Java language
+
+@ignore
+@c man begin SYNOPSIS gcj
+gcj [@option{-I}@var{dir}@dots{}] [@option{-d} @var{dir}@dots{}]
+ [@option{--CLASSPATH}=@var{path}] [@option{--classpath}=@var{path}]
+ [@option{-f}@var{option}@dots{}] [@option{--encoding}=@var{name}]
+ [@option{--main}=@var{classname}] [@option{-D}@var{name}[=@var{value}]@dots{}]
+ [@option{-C}] [@option{--resource} @var{resource-name}] [@option{-d} @var{directory}]
+ [@option{-W}@var{warn}@dots{}]
+ @var{sourcefile}@dots{}
+@c man end
+@c man begin SEEALSO gcj
+gcc(1), gcjh(1), gjnih(1), gij(1), jcf-dump(1), gfdl(7),
+and the Info entries for @file{gcj} and @file{gcc}.
+@c man end
+@end ignore
+
+@c man begin DESCRIPTION gcj
+
+As @command{gcj} is just another front end to @command{gcc}, it supports many
of the same options as gcc. @xref{Option Summary, , Option Summary,
-gcc, Using the GNU Compiler Collection}. This manual only documents the
-options specific to @code{gcj}.
+gcc, Using the GNU Compiler Collection (GCC)}. This manual only documents the
+options specific to @command{gcj}.
+
+@c man end
@menu
* Input and output files::
* Input Options:: How gcj finds files
* Encodings:: Options controlling source file encoding
* Warnings:: Options controlling warnings specific to gcj
+* Linking:: Options for making an executable
* Code Generation:: Options controlling the output of gcj
* Configure-time Options:: Options you won't use
@end menu
+@c man begin OPTIONS gcj
+
@node Input and output files
@section Input and output files
-A @code{gcj} command is like a @code{gcc} command, in that it
+A @command{gcj} command is like a @command{gcc} command, in that it
consists of a number of options and file names. The following kinds
of input file names are supported:
-@table @code
+@table @gcctabopt
@item @var{file}.java
Java source files.
@item @var{file}.class
@item @var{file}.zip
@itemx @var{file}.jar
An archive containing one or more @code{.class} files, all of
-which are compiled. The archive may be compressed.
+which are compiled. The archive may be compressed. Files in
+an archive which don't end with @samp{.class} are treated as
+resource files; they are compiled into the resulting object file
+as @samp{core:} URLs.
@item @@@var{file}
A file containing a whitespace-separated list of input file names.
(Currently, these must all be @code{.java} source files, but that
@item @var{library}.a
@itemx @var{library}.so
@itemx -l@var{libname}
-Libraries to use when linking. See the @code{gcc} manual.
+Libraries to use when linking. See the @command{gcc} manual.
@end table
-You can specify more than one input file on the @code{gcj} command line,
+You can specify more than one input file on the @command{gcj} command line,
in which case they will all be compiled. If you specify a
@code{-o @var{FILENAME}}
option, all the input files will be compiled together, producing a
single output file, named @var{FILENAME}.
This is allowed even when using @code{-S} or @code{-c},
-but not when using @code{-C}.
-(This is an extension beyond the what plain @code{gcc} allows.)
+but not when using @code{-C} or @code{--resource}.
+(This is an extension beyond the what plain @command{gcc} allows.)
(If more than one input file is specified, all must currently
be @code{.java} files, though we hope to fix this.)
@cindex class path
-@code{gcj} has options to control where it looks to find files it needs.
-For instance, @code{gcj} might need to load a class that is referenced
+@command{gcj} has options to control where it looks to find files it needs.
+For instance, @command{gcj} might need to load a class that is referenced
by the file it has been asked to compile. Like other compilers for the
-Java language, @code{gcj} has a notion of a @dfn{class path}. There are
+Java language, @command{gcj} has a notion of a @dfn{class path}. There are
several options and environment variables which can be used to
-manipulate the class path. When @code{gcj} looks for a given class, it
+manipulate the class path. When @command{gcj} looks for a given class, it
searches the class path looking for matching @file{.class} or
-@file{.java} file. @code{gcj} comes with a built-in class path which
+@file{.java} file. @command{gcj} comes with a built-in class path which
points at the installed @file{libgcj.jar}, a file which contains all the
standard classes.
-In the below, a directory or path component can refer either to an
+In the text below, a directory or path component can refer either to an
actual directory on the filesystem, or to a @file{.zip} or @file{.jar}
-file, which @code{gcj} will search as if it is a directory.
+file, which @command{gcj} will search as if it is a directory.
-@table @code
+@table @gcctabopt
@item -I@var{dir}
All directories specified by @code{-I} are kept in order and prepended
to the class path constructed from all the other options. Unless
-compatibility with tools like @code{javac} is imported, we recommend
+compatibility with tools like @code{javac} is important, we recommend
always using @code{-I} instead of the other options for manipulating the
class path.
@item --classpath=@var{path}
This sets the class path to @var{path}, a colon-separated list of paths
(on Windows-based systems, a semicolon-separate list of paths).
+This does not override the builtin (``boot'') search path.
@item --CLASSPATH=@var{path}
-This sets the class path to @var{path}, a colon-separated list of paths
-(on Windows-based systems, a semicolon-separate list of paths). This
-differs from the @code{--classpath} option in that it also suppresses
-the built-in system path.
+Deprecated synonym for @code{--classpath}.
+
+@item --bootclasspath=@var{path}
+Where to find the standard builtin classes, such as @code{java.lang.String}.
+
+@item --extdirs=@var{path}
+For each directory in the @var{path}, place the contents of that
+directory at the end of the class path.
@item CLASSPATH
This is an environment variable which holds a list of paths.
First come all directories specified via @code{-I}.
@item
-If @code{--classpath} is specified, its value is appended and processing
-stops. That is, @code{--classpath} suppresses all the options mentioned
-later in this list.
-
-@item
-If @code{--CLASSPATH} is specified, its value is appended and the
-@code{CLASSPATH} environment variable is suppressed.
+If @option{--classpath} is specified, its value is appended.
+Otherwise, if the @code{CLASSPATH} environment variable is specified,
+then its value is appended.
+Otherwise, the current directory (@code{"."}) is appended.
@item
-If the @code{CLASSPATH} environment variable is specified (and was not
-suppressed by @code{--CLASSPATH}), then its value is appended.
+If @code{--bootclasspath} was specified, append its value.
+Otherwise, append the built-in system directory, @file{libgcj.jar}.
@item
-Finally, the built-in system directory, @file{libgcj.jar}, is appended.
+Finally, if @code{--extdirs} was specified, append the contents of the
+specified directories at the end of the class path. Otherwise, append
+the contents of the built-in extdirs at @code{$(prefix)/share/java/ext}.
@end itemize
-The classfile built by @code{gcj} for the class @code{java.lang.Object}
+The classfile built by @command{gcj} for the class @code{java.lang.Object}
(and placed in @code{libgcj.jar}) contains a special zero length
attribute @code{gnu.gcj.gcj-compiled}. The compiler looks for this
attribute when loading @code{java.lang.Object} and will report an error
if it isn't found, unless it compiles to bytecode (the option
-@code{-fforce-classes-archive-check} can be used to overide this
+@code{-fforce-classes-archive-check} can be used to override this
behavior in this particular case.)
-@table @code
+@table @gcctabopt
@item -fforce-classes-archive-check
This forces the compiler to always check for the special zero length
attribute @code{gnu.gcj.gcj-compiled} in @code{java.lang.Object} and
issue an error if it isn't found.
+
+@item -fsource=@var{VERSION}
+This option is used to choose the source version accepted by
+@command{gcj}. The default is @samp{1.5}.
@end table
@node Encodings
@section Encodings
The Java programming language uses Unicode throughout. In an effort to
-integrate well with other locales, @code{gcj} allows @file{.java} files
-to be written using almost any encoding. @code{gcj} knows how to
+integrate well with other locales, @command{gcj} allows @file{.java} files
+to be written using almost any encoding. @command{gcj} knows how to
convert these encodings into its internal encoding at compile time.
You can use the @code{--encoding=@var{NAME}} option to specify an
encoding (of a particular character set) to use for source files. If
this is not specified, the default encoding comes from your current
locale. If your host system has insufficient locale support, then
-@code{gcj} assumes the default encoding to be the @samp{UTF-8} encoding
+@command{gcj} assumes the default encoding to be the @samp{UTF-8} encoding
of Unicode.
-To implement @code{--encoding}, @code{gcj} simply uses the host
+To implement @code{--encoding}, @command{gcj} simply uses the host
platform's @code{iconv} conversion routine. This means that in practice
-@code{gcj} is limited by the capabilities of the host platform.
+@command{gcj} is limited by the capabilities of the host platform.
The names allowed for the argument @code{--encoding} vary from platform
to platform (since they are not standardized anywhere). However,
-@code{gcj} implements the encoding named @samp{UTF-8} internally, so if
+@command{gcj} implements the encoding named @samp{UTF-8} internally, so if
you choose to use this for your source files you can be assured that it
will work on every host.
@node Warnings
@section Warnings
-@code{gcj} implements several warnings. As with other generic
-@code{gcc} warnings, if an option of the form @code{-Wfoo} enables a
+@command{gcj} implements several warnings. As with other generic
+@command{gcc} warnings, if an option of the form @code{-Wfoo} enables a
warning, then @code{-Wno-foo} will disable it. Here we've chosen to
document the form of the warning which will have an effect -- the
default being the opposite of what is listed.
-@table @code
+@table @gcctabopt
@item -Wredundant-modifiers
-With this flag, @code{gcj} will warn about redundant modifiers. For
+With this flag, @command{gcj} will warn about redundant modifiers. For
instance, it will warn if an interface method is declared @code{public}.
@item -Wextraneous-semicolon
-This causes @code{gcj} to warn about empty statements. Empty statements
+This causes @command{gcj} to warn about empty statements. Empty statements
have been deprecated.
@item -Wno-out-of-date
-This option will cause @code{gcj} not to warn when a source file is
-newer than its matching class file. By default @code{gcj} will warn
+This option will cause @command{gcj} not to warn when a source file is
+newer than its matching class file. By default @command{gcj} will warn
about this.
+@item -Wno-deprecated
+Warn if a deprecated class, method, or field is referred to.
+
@item -Wunused
-This is the same as @code{gcc}'s @code{-Wunused}.
+This is the same as @command{gcc}'s @code{-Wunused}.
@item -Wall
This is the same as @code{-Wredundant-modifiers -Wextraneous-semicolon
@end table
-@node Code Generation
-@section Code Generation
+@node Linking
+@section Linking
-In addition to the many @code{gcc} options controlling code generation,
-@code{gcj} has several options specific to itself.
+To turn a Java application into an executable program,
+you need to link it with the needed libraries, just as for C or C++.
+The linker by default looks for a global function named @code{main}.
+Since Java does not have global functions, and a
+collection of Java classes may have more than one class with a
+@code{main} method, you need to let the linker know which of those
+@code{main} methods it should invoke when starting the application.
+You can do that in any of these ways:
-@table @code
+@itemize @bullet
+@item
+Specify the class containing the desired @code{main} method
+when you link the application, using the @code{--main} flag,
+described below.
+@item
+Link the Java package(s) into a shared library (dll) rather than an
+executable. Then invoke the application using the @code{gij} program,
+making sure that @code{gij} can find the libraries it needs.
+@item
+Link the Java packages(s) with the flag @code{-lgij}, which links
+in the @code{main} routine from the @code{gij} command.
+This allows you to select the class whose @code{main} method you
+want to run when you run the application. You can also use
+other @code{gij} flags, such as @code{-D} flags to set properties.
+Using the @code{-lgij} library (rather than the @code{gij} program
+of the previous mechanism) has some advantages: it is compatible with
+static linking, and does not require configuring or installing libraries.
+@end itemize
+
+These @code{gij} options relate to linking an executable:
+
+@table @gcctabopt
@item --main=@var{CLASSNAME}
This option is used when linking to specify the name of the class whose
@code{main} method should be invoked when the resulting executable is
-run. @footnote{The linker by default looks for a global function named
-@code{main}. Since Java does not have global functions, and a
-collection of Java classes may have more than one class with a
-@code{main} method, you need to let the linker know which of those
-@code{main} methods it should invoke when starting the application.}
+run.
@item -D@var{name}[=@var{value}]
This option can only be used with @code{--main}. It defines a system
are initialized at the program's startup and can be retrieved at runtime
using the @code{java.lang.System.getProperty} method.
+@item -lgij
+Create an application whose command-line processing is that
+of the @code{gij} command.
+
+This option is an alternative to using @code{--main}; you cannot use both.
+
+@item -static-libgcj
+This option causes linking to be done against a static version of the
+libgcj runtime library. This option is only available if
+corresponding linker support exists.
+
+@strong{Caution:} Static linking of libgcj may cause essential parts
+of libgcj to be omitted. Some parts of libgcj use reflection to load
+classes at runtime. Since the linker does not see these references at
+link time, it can omit the referred to classes. The result is usually
+(but not always) a @code{ClassNotFoundException} being thrown at
+runtime. Caution must be used when using this option. For more
+details see:
+@w{@uref{http://gcc.gnu.org/wiki/Statically%20linking%20libgcj}}
+@end table
+
+@node Code Generation
+@section Code Generation
+
+In addition to the many @command{gcc} options controlling code generation,
+@command{gcj} has several options specific to itself.
+
+@table @gcctabopt
+
@item -C
-This option is used to tell @code{gcj} to generate bytecode
+This option is used to tell @command{gcj} to generate bytecode
(@file{.class} files) rather than object code.
+@item --resource @var{resource-name}
+This option is used to tell @command{gcj} to compile the contents of a
+given file to object code so it may be accessed at runtime with the core
+protocol handler as @samp{core:/@var{resource-name}}. Note that
+@var{resource-name} is the name of the resource as found at runtime; for
+instance, it could be used in a call to @code{ResourceBundle.getBundle}.
+The actual file name to be compiled this way must be specified
+separately.
+
+@item -ftarget=@var{VERSION}
+This can be used with @option{-C} to choose the version of bytecode
+emitted by @command{gcj}. The default is @samp{1.5}. When not
+generating bytecode, this option has no effect.
+
@item -d @var{directory}
When used with @code{-C}, this causes all generated @file{.class} files
to be put in the appropriate subdirectory of @var{directory}. By
directory.
@item -fno-bounds-check
-By default, @code{gcj} generates code which checks the bounds of all
-array indexing operations. With this option, these checks are omitted.
-Note that this can result in unpredictable behavior if the code in
-question actually does violate array bounds constraints.
+By default, @command{gcj} generates code which checks the bounds of all
+array indexing operations. With this option, these checks are omitted, which
+can improve performance for code that uses arrays extensively. Note that this
+can result in unpredictable behavior if the code in question actually does
+violate array bounds constraints. It is safe to use this option if you are
+sure that your code will never throw an @code{ArrayIndexOutOfBoundsException}.
+
+@item -fno-store-check
+Don't generate array store checks. When storing objects into arrays, a runtime
+check is normally generated in order to ensure that the object is assignment
+compatible with the component type of the array (which may not be known
+at compile-time). With this option, these checks are omitted. This can
+improve performance for code which stores objects into arrays frequently.
+It is safe to use this option if you are sure your code will never throw an
+@code{ArrayStoreException}.
@item -fjni
-With @code{gcj} there are two options for writing native methods: CNI
-and JNI. By default @code{gcj} assumes you are using CNI. If you are
+With @command{gcj} there are two options for writing native methods: CNI
+and JNI@. By default @command{gcj} assumes you are using CNI@. If you are
compiling a class with native methods, and these methods are implemented
using JNI, then you must use @code{-fjni}. This option causes
-@code{gcj} to generate stubs which will invoke the underlying JNI
+@command{gcj} to generate stubs which will invoke the underlying JNI
methods.
+
+@item -fno-assert
+Don't recognize the @code{assert} keyword. This is for compatibility
+with older versions of the language specification.
+
+@item -fno-optimize-static-class-initialization
+When the optimization level is greater or equal to @code{-O2},
+@command{gcj} will try to optimize the way calls into the runtime are made
+to initialize static classes upon their first use (this optimization
+isn't carried out if @code{-C} was specified.) When compiling to native
+code, @code{-fno-optimize-static-class-initialization} will turn this
+optimization off, regardless of the optimization level in use.
+
+@item --disable-assertions[=@var{class-or-package}]
+Don't include code for checking assertions in the compiled code.
+If @code{=@var{class-or-package}} is missing disables assertion code
+generation for all classes, unless overridden by a more
+specific @code{--enable-assertions} flag.
+If @var{class-or-package} is a class name, only disables generating
+assertion checks within the named class or its inner classes.
+If @var{class-or-package} is a package name, disables generating
+assertion checks within the named package or a subpackage.
+
+By default, assertions are enabled when generating class files
+or when not optimizing, and disabled when generating optimized binaries.
+
+@item --enable-assertions[=@var{class-or-package}]
+Generates code to check assertions. The option is perhaps misnamed,
+as you still need to turn on assertion checking at run-time,
+and we don't support any easy way to do that.
+So this flag isn't very useful yet, except to partially override
+@code{--disable-assertions}.
+
+@item -findirect-dispatch
+@command{gcj} has a special binary compatibility ABI, which is enabled
+by the @code{-findirect-dispatch} option. In this mode, the code
+generated by @command{gcj} honors the binary compatibility guarantees
+in the Java Language Specification, and the resulting object files do
+not need to be directly linked against their dependencies. Instead,
+all dependencies are looked up at runtime. This allows free mixing of
+interpreted and compiled code.
+
+Note that, at present, @code{-findirect-dispatch} can only be used
+when compiling @file{.class} files. It will not work when compiling
+from source. CNI also does not yet work with the binary compatibility
+ABI. These restrictions will be lifted in some future release.
+
+However, if you compile CNI code with the standard ABI, you can call
+it from code built with the binary compatibility ABI.
+
+@item -fbootstrap-classes
+This option can be use to tell @code{libgcj} that the compiled classes
+should be loaded by the bootstrap loader, not the system class loader.
+By default, if you compile a class and link it into an executable, it
+will be treated as if it was loaded using the system class loader.
+This is convenient, as it means that things like
+@code{Class.forName()} will search @samp{CLASSPATH} to find the
+desired class.
+
+@item -freduced-reflection
+This option causes the code generated by @command{gcj} to contain a
+reduced amount of the class meta-data used to support runtime
+reflection. The cost of this savings is the loss of
+the ability to use certain reflection capabilities of the standard
+Java runtime environment. When set all meta-data except for that
+which is needed to obtain correct runtime semantics is eliminated.
+
+For code that does not use reflection (i.e. the methods in the
+@code{java.lang.reflect} package), @code{-freduced-reflection}
+will result in proper operation with a savings in executable code size.
+
+JNI (@code{-fjni}) and the binary compatibility ABI
+(@code{-findirect-dispatch}) do not work properly without full
+reflection meta-data. Because of this, it is an error to use these options
+with @code{-freduced-reflection}.
+
+@strong{Caution:} If there is no reflection meta-data, code that uses
+a @code{SecurityManager} may not work properly. Also calling
+@code{Class.forName()} may fail if the calling method has no
+reflection meta-data.
+
@end table
@node Configure-time Options
@section Configure-time Options
-Some @code{gcj} code generations options affect the resulting ABI, and
+Some @command{gcj} code generations options affect the resulting ABI, and
so can only be meaningfully given when @code{libgcj}, the runtime
package, is configured. @code{libgcj} puts the appropriate options from
-this group into a @samp{spec} file which is read by @code{gcj}. These
+this group into a @samp{spec} file which is read by @command{gcj}. These
options are listed here for completeness; if you are using @code{libgcj}
then you won't want to touch these options.
-@table @code
+@table @gcctabopt
@item -fuse-boehm-gc
This enables the use of the Boehm GC bitmap marking code. In particular
-this causes @code{gcj} to put an object marking descriptor into each
+this causes @command{gcj} to put an object marking descriptor into each
vtable.
@item -fhash-synchronization
By default, synchronization data (the data used for @code{synchronize},
@code{wait}, and @code{notify}) is pointed to by a word in each object.
-With this option @code{gcj} assumes that this information is stored in a
+With this option @command{gcj} assumes that this information is stored in a
hash table and not in the object itself.
@item -fuse-divide-subroutine
processor.
@end table
+@c man end
@node Compatibility
@chapter Compatibility with the Java Platform
As we believe it is important that the Java platform not be fragmented,
-@code{gcj} and @code{libgcj} try to conform to the relevant Java
+@command{gcj} and @code{libgcj} try to conform to the relevant Java
specifications. However, limited manpower and incomplete and unclear
documentation work against us. So, there are caveats to using
-@code{gcj}.
+@command{gcj}.
+
+@menu
+* Limitations::
+* Extensions::
+@end menu
+
+@node Limitations
+@section Standard features not yet supported
This list of compatibility issues is by no means complete.
@itemize @bullet
@item
-@code{gcj} implements the JDK 1.1 language. It supports inner classes,
-though these are known to still be buggy. It does not yet support the
-Java 2 @code{strictfp} keyword (it recognizes the keyword but ignores
-it).
+@command{gcj} implements the JDK 1.2 language. It supports inner classes
+and the new 1.4 @code{assert} keyword. It does not yet support the Java 2
+@code{strictfp} keyword (it recognizes the keyword but ignores it).
@item
@code{libgcj} is largely compatible with the JDK 1.2 libraries.
from the JDK implementation. This is not always a bug. Still, if it
affects you, it probably makes sense to report it so that we can discuss
the appropriate response.
-@end itemize
+@item
+@command{gcj} does not currently allow for piecemeal replacement of
+components within @code{libgcj}. Unfortunately, programmers often want
+to use newer versions of certain packages, such as those provided by
+the Apache Software Foundation's Jakarta project. This has forced us
+to place the @code{org.w3c.dom} and @code{org.xml.sax} packages into
+their own libraries, separate from @code{libgcj}. If you intend to
+use these classes, you must link them explicitly with
+@code{-l-org-w3c-dom} and @code{-l-org-xml-sax}. Future versions of
+@command{gcj} may not have this restriction.
+@end itemize
-@node Invoking gcjh
-@chapter Invoking gcjh
-
-The @code{gcjh} program is used to generate header files from class
-files. It can generate both CNI and JNI header files, as well as stub
-implementation files which can be used as a basis for implementing the
-required native methods.
-
-@table @code
-@item -stubs
-This causes @code{gcjh} to generate stub files instead of header files.
-By default the stub file will be named after the class, with a suffix of
-@samp{.cc}. In JNI mode, the default output file will have the suffix
-@samp{.c}.
-
-@item -jni
-This tells @code{gcjh} to generate a JNI header or stub. By default,
-CNI headers are generated.
-
-@item -add @var{text}
-Inserts @var{text} into the class body. This is ignored in JNI mode.
-
-@item -append @var{text}
-Inserts @var{text} into the header file after the class declaration.
-This is ignored in JNI mode.
-
-@item -friend @var{text}
-Inserts @var{text} into the class as a @code{friend} declaration.
-This is ignored in JNI mode.
-
-@item -prepend @var{text}
-Inserts @var{text} into the header file before the class declaration.
-This is ignored in JNI mode.
-
-@item --classpath=@var{path}
-@itemx --CLASSPATH=@var{path}
-@itemx -I@var{directory}
-@itemx -d @var{directory}
-@itemx -o @var{file}
-These options are all identical to the corresponding @code{gcj} options.
-
-@item -o @var{file}
-Sets the output file name. This cannot be used if there is more than
-one class on the command line.
-
-@item -td @var{directory}
-Sets the name of the directory to use for temporary files.
-
-@item --help
-Print help about @code{gcjh} and exit. No further processing is done.
-
-@item --version
-Print version information for @code{gcjh} and exit. No further
-processing is done.
-@end table
+@node Extensions
+@section Extra features unique to gcj
-All remaining options are considered to be names of classes.
+The main feature of @command{gcj} is that it can compile programs written in
+the Java programming language to native code. Most extensions that have been
+added are to facilitate this functionality.
+@itemize @bullet
+@item
+@command{gcj} makes it easy and efficient to mix code written in Java and C++.
+@xref{About CNI}, for more info on how to use this in your programs.
-@node Invoking jv-scan
-@chapter Invoking jv-scan
+@item
+When you compile your classes into a shared library using
+@code{-findirect-dispatch} then add them to the system-wide
+classmap.db file using @code{gcj-dbtool}, they will be automatically
+loaded by the @code{libgcj} system classloader. This is the new,
+preferred classname-to-library resolution mechanism. @xref{Invoking
+gcj-dbtool}, for more information on using the classmap database.
-The @code{jv-scan} program can be used to print information about a Java
-source file (@file{.java} file).
+@item
+The old classname-to-library lookup mechanism is still supported
+through the @code{gnu.gcj.runtime.VMClassLoader.library_control}
+property, but it is deprecated and will likely be removed in some
+future release. When trying to load a class @code{gnu.pkg.SomeClass}
+the system classloader will first try to load the shared library
+@file{lib-gnu-pkg-SomeClass.so}, if that fails to load the class then
+it will try to load @file{lib-gnu-pkg.so} and finally when the class
+is still not loaded it will try to load @file{lib-gnu.so}. Note that
+all @samp{.}s will be transformed into @samp{-}s and that searching
+for inner classes starts with their outermost outer class. If the
+class cannot be found this way the system classloader tries to use the
+@code{libgcj} bytecode interpreter to load the class from the standard
+classpath. This process can be controlled to some degree via the
+@code{gnu.gcj.runtime.VMClassLoader.library_control} property;
+@xref{libgcj Runtime Properties}.
-@table @code
-@item --complexity
-This prints a complexity measure, related to cyclomatic complexity, for
-each input file.
+@item
+@code{libgcj} includes a special @samp{gcjlib} URL type. A URL of
+this form is like a @code{jar} URL, and looks like
+@samp{gcjlib:/path/to/shared/library.so!/path/to/resource}. An access
+to one of these URLs causes the shared library to be @code{dlopen()}d,
+and then the resource is looked for in that library. These URLs are
+most useful when used in conjunction with @code{java.net.URLClassLoader}.
+Note that, due to implementation limitations, currently any such URL
+can be accessed by only one class loader, and libraries are never
+unloaded. This means some care must be exercised to make sure that
+a @code{gcjlib} URL is not accessed by more than one class loader at once.
+In a future release this limitation will be lifted, and such
+libraries will be mapped privately.
-@item --encoding=@var{name}
-This works like the corresponding @code{gcj} option.
+@item
+A program compiled by @command{gcj} will examine the
+@env{GCJ_PROPERTIES} environment variable and change its behavior in
+some ways. In particular @env{GCJ_PROPERTIES} holds a list of
+assignments to global properties, such as would be set with the
+@option{-D} option to @command{java}. For instance,
+@samp{java.compiler=gcj} is a valid (but currently meaningless)
+setting.
+@cindex GCJ_PROPERTIES
+@vindex GCJ_PROPERTIES
-@item --print-main
-This prints the name of the class in this file containing a @code{main}
-method.
+@end itemize
-@item --list-class
-This lists the names of all classes defined in the input files.
-@item --list-filename
-If @code{--list-class} is given, this option causes @code{jv-scan} to
-also print the name of the file in which each class was found.
+@node Invoking jcf-dump
+@chapter Invoking jcf-dump
-@item -o @var{file}
-Print output to the named file.
-@end table
+@c man title jcf-dump print information about Java class files
+@ignore
+@c man begin SYNOPSIS jcf-dump
+jcf-dump [@option{-c}] [@option{--javap}]
+ [@option{--classpath}=@var{path}] [@option{--CLASSPATH}=@var{path}]
+ [@option{-I}@var{dir}@dots{}] [@option{-o} @var{file}]
+ [@option{--version}] [@option{--help}] [@option{-v}] [@option{--verbose}]
+ @var{classname}@dots{}
+@c man end
+@c man begin SEEALSO jcf-dump
+gcc(1), gcj(1), gcjh(1), gij(1), jcf-dump(1), gfdl(7),
+and the Info entries for @file{gcj} and @file{gcc}.
+@c man end
+@end ignore
-@node Invoking jcf-dump
-@chapter Invoking jcf-dump
+@c man begin DESCRIPTION jcf-dump
This is a class file examiner, similar to @code{javap}. It will print
-information about a number of classes, which are specifed by class name
+information about a number of classes, which are specified by class name
or file name.
-@table @code
+@c man end
+
+@c man begin OPTIONS jcf-dump
+
+@table @gcctabopt
@item -c
Disassemble method bodies. By default method bodies are not printed.
+@item --print-constants
+Print the constant pool. When printing a reference to a constant
+also print its index in the constant pool.
+
@item --javap
Generate output in @code{javap} format. The implementation of this
feature is very incomplete.
@itemx --CLASSPATH=@var{path}
@itemx -I@var{directory}
@itemx -o @var{file}
-These options as the same as the corresponding @code{gcj} options.
+These options as the same as the corresponding @command{gcj} options.
+
+@item --help
+Print help, then exit.
+
+@item --version
+Print version number, then exit.
+
+@item -v, --verbose
+Print extra information while running.
+Implies @code{--print-constants}.
@end table
+@c man end
@node Invoking gij
@chapter Invoking gij
+@c man title gij GNU interpreter for Java bytecode
+
+@ignore
+@c man begin SYNOPSIS gij
+gij [@option{OPTION}] @dots{} @var{JARFILE} [@var{ARGS}@dots{}]
+
+gij [@option{-jar}] [@option{OPTION}] @dots{} @var{CLASS} [@var{ARGS}@dots{}]
+ [@option{-cp} @var{path}] [@option{-classpath} @var{path}]
+ [@option{-D}@var{name}[=@var{value}]@dots{}]
+ [@option{-ms=}@var{number}] [@option{-mx=}@var{number}]
+ [@option{-X@var{argument}}] [@option{-verbose}] [@option{-verbose:class}]
+ [@option{--showversion}] [@option{--version}] [@option{--help}][@option{-?}]
+@c man end
+@c man begin SEEALSO gij
+gcc(1), gcj(1), gcjh(1), jcf-dump(1), gfdl(7),
+and the Info entries for @file{gcj} and @file{gcc}.
+@c man end
+@end ignore
+
+@c man begin DESCRIPTION gij
+
@code{gij} is a Java bytecode interpreter included with @code{libgcj}.
@code{gij} is not available on every platform; porting it requires a
small amount of assembly programming which has not been done for all the
-targets supported by @code{gcj}.
+targets supported by @command{gcj}.
The primary argument to @code{gij} is the name of a class or, with
@code{-jar}, a jar file. Options before this argument are interpreted
objects, it is possible to give @code{gij} the name of a class which has
been compiled and put into a shared library on the class path.
-@table @code
+@c man end
+
+@c man begin OPTIONS gij
+
+@table @gcctabopt
+@item -cp @var{path}
+@itemx -classpath @var{path}
+Set the initial class path. The class path is used for finding
+class and resource files. If specified, this option overrides the
+@code{CLASSPATH} environment variable. Note that this option is
+ignored if @code{-jar} is used.
+
@item -D@var{name}[=@var{value}]
This defines a system property named @var{name} with value @var{value}.
If @var{value} is not specified then it defaults to the empty string.
method.
@item -ms=@var{number}
-This sets the initial heap size
+Equivalent to @code{-Xms}.
@item -mx=@var{number}
-This sets the maximum heap size.
+Equivalent to @code{-Xmx}.
+
+@item -noverify
+Do not verify compliance of bytecode with the VM specification. In addition,
+this option disables type verification which is otherwise performed on BC-ABI
+compiled code.
+
+@item -X
+@itemx -X@var{argument}
+Supplying @code{-X} by itself will cause @code{gij} to list all the
+supported @code{-X} options. Currently these options are supported:
+
+@table @gcctabopt
+@item -Xms@var{size}
+Set the initial heap size.
+
+@item -Xmx@var{size}
+Set the maximum heap size.
+
+@item -Xss@var{size}
+Set the thread stack size.
+@end table
+
+Unrecognized @code{-X} options are ignored, for compatibility with
+other runtimes.
@item -jar
This indicates that the name passed to @code{gij} should be interpreted
as the name of a jar file, not a class.
+
+@item --help
+@itemx -?
+Print help, then exit.
+
+@item --showversion
+Print version number and continue.
+
+@item --fullversion
+Print detailed version information, then exit.
+
+@item --version
+Print version number, then exit.
+
+@item -verbose
+@itemx -verbose:class
+Each time a class is initialized, print a short message on standard error.
+@end table
+
+@code{gij} also recognizes and ignores the following options, for
+compatibility with existing application launch scripts:
+@code{-client}, @code{-server}, @code{-hotspot}, @code{-jrockit},
+@code{-agentlib}, @code{-agentpath}, @code{-debug}, @code{-d32},
+@code{-d64}, @code{-javaagent}, @code{-noclassgc}, @code{-verify},
+and @code{-verifyremote}.
+
+@c man end
+
+@node Invoking gcj-dbtool
+@chapter Invoking gcj-dbtool.
+
+@c man title gcj-dbtool Manipulate class file mapping databases for libgcj
+
+@ignore
+@c man begin SYNOPSIS gcj-dbtool
+gcj-dbtool @option{OPTION} @var{DBFILE} [@option{MORE}] @dots{}
+
+gcj-dbtool [@option{-0}] [@option{-}] [@option{-n}] [@option{-a}] [@option{-f}]
+ [@option{-t}] [@option{-l}] [@option{-p} [@var{LIBDIR}]]
+ [@option{-v}] [@option{-m}] [@option{--version}] [@option{--help}]
+
+@c man end
+@c man begin SEEALSO gij
+gcc(1), gcj(1), gcjh(1), jcf-dump(1), gfdl(7),
+and the Info entries for @file{gcj} and @file{gcc}.
+@c man end
+@end ignore
+
+@c man begin DESCRIPTION gcj-dbtool
+
+@code{gcj-dbtool} is a tool for creating and manipulating class file
+mapping databases. @code{libgcj} can use these databases to find a
+shared library corresponding to the bytecode representation of a
+class. This functionality is useful for ahead-of-time compilation of
+a program that has no knowledge of @code{gcj}.
+
+@code{gcj-dbtool} works best if all the jar files added to it are
+compiled using @code{-findirect-dispatch}.
+
+Note that @code{gcj-dbtool} is currently available as ``preview
+technology''. We believe it is a reasonable way to allow
+application-transparent ahead-of-time compilation, but this is an
+unexplored area. We welcome your comments.
+
+@c man end
+
+@c man begin OPTIONS gcj-dbtool
+
+@table @gcctabopt
+@item -n @var{DBFILE} [@var{SIZE}]
+This creates a new database. Currently, databases cannot be resized;
+you can choose a larger initial size if desired. The default size is
+32,749.
+
+@item -a @var{DBFILE} @var{JARFILE} @var{LIB}
+@itemx -f @var{DBFILE} @var{JARFILE} @var{LIB}
+This adds a jar file to the database. For each class file in the jar,
+a cryptographic signature of the bytecode representation of the class
+is recorded in the database. At runtime, a class is looked up by its
+signature and the compiled form of the class is looked for in the
+corresponding shared library. The @option{-a} option will verify
+that @var{LIB} exists before adding it to the database; @option{-f}
+skips this check.
+
+@item [@option{-}][@option{-0}] -m @var{DBFILE} @var{DBFILE},[@var{DBFILE}]
+Merge a number of databases. The output database overwrites any
+existing database. To add databases into an existing database,
+include the destination in the list of sources.
+
+If @option{-} or @option{-0} are used, the list of files to read is
+taken from standard input instead of the command line. For
+@option{-0}, Input filenames are terminated by a null character
+instead of by whitespace. Useful when arguments might contain white
+space. The GNU find -print0 option produces input suitable for this
+mode.
+
+@item -t @var{DBFILE}
+Test a database.
+
+@item -l @var{DBFILE}
+List the contents of a database.
+
+@item -p
+Print the name of the default database. If there is no default
+database, this prints a blank line. If @var{LIBDIR} is specified, use
+it instead of the default library directory component of the database
+name.
+
+@item --help
+Print a help message, then exit.
+
+@item --version
+@itemx -v
+Print version information, then exit.
+
+@end table
+
+@c man end
+
+@node Invoking jv-convert
+@chapter Invoking jv-convert
+
+@c man title jv-convert Convert file from one encoding to another
+
+@c man begin SYNOPSIS jv-convert
+@command{jv-convert} [@option{OPTION}] @dots{} [@var{INPUTFILE} [@var{OUTPUTFILE}]]
+@ignore
+
+ [@option{--encoding} @var{name}]
+ [@option{--from} @var{name}]
+ [@option{--to} @var{name}]
+ [@option{-i} @var{file}] [@option{-o} @var{file}]
+ [@option{--reverse}] [@option{--help}] [@option{--version}]
+@end ignore
+@c man end
+
+@c man begin DESCRIPTION jv-convert
+
+@command{jv-convert} is a utility included with @code{libgcj} which
+converts a file from one encoding to another. It is similar to the Unix
+@command{iconv} utility.
+
+The encodings supported by @command{jv-convert} are platform-dependent.
+Currently there is no way to get a list of all supported encodings.
+
+@c man end
+
+@c man begin OPTIONS jv-convert
+
+@table @gcctabopt
+@item --encoding @var{name}
+@itemx --from @var{name}
+Use @var{name} as the input encoding. The default is the current
+locale's encoding.
+
+@item --to @var{name}
+Use @var{name} as the output encoding. The default is the
+@code{JavaSrc} encoding; this is ASCII with @samp{\u} escapes for
+non-ASCII characters.
+
+@item -i @var{file}
+Read from @var{file}. The default is to read from standard input.
+
+@item -o @var{file}
+Write to @var{file}. The default is to write to standard output.
+
+@item --reverse
+Swap the input and output encodings.
+
+@item --help
+Print a help message, then exit.
+
+@item --version
+Print version information, then exit.
+@end table
+
+@c man end
+
+@node Invoking grmic
+@chapter Invoking grmic
+
+@c man title grmic Generate stubs for Remote Method Invocation
+
+@c man begin SYNOPSIS grmic
+@command{grmic} [@option{OPTION}] @dots{} @var{class} @dots{}
+@ignore
+ [@option{-keep}]
+ [@option{-keepgenerated}]
+ [@option{-v1.1}]
+ [@option{-vcompat}]
+ [@option{-v1.2}]
+ [@option{-nocompile}]
+ [@option{-verbose}]
+ [@option{-d} @var{directory}]
+ [@option{-help}]
+ [@option{-version}]
+@end ignore
+@c man end
+
+@c man begin DESCRIPTION grmic
+
+@command{grmic} is a utility included with @code{libgcj} which generates
+stubs for remote objects.
+
+@c FIXME: Add real information here.
+@c This really isn't much more than the --help output.
+
+Note that this program isn't yet fully compatible with the JDK
+@command{grmic}. Some options, such as @option{-classpath}, are
+recognized but currently ignored. We have left these options
+undocumented for now.
+
+Long options can also be given with a GNU-style leading @samp{--}. For
+instance, @option{--help} is accepted.
+
+@c man end
+
+@c man begin OPTIONS grmic
+
+@table @gcctabopt
+@item -keep
+@itemx -keepgenerated
+By default, @command{grmic} deletes intermediate files. Either of these
+options causes it not to delete such files.
+
+@item -v1.1
+Cause @command{grmic} to create stubs and skeletons for the 1.1
+protocol version.
+
+@item -vcompat
+Cause @command{grmic} to create stubs and skeletons compatible with both
+the 1.1 and 1.2 protocol versions. This is the default.
+
+@item -v1.2
+Cause @command{grmic} to create stubs and skeletons for the 1.2
+protocol version.
+
+@item -nocompile
+Don't compile the generated files.
+
+@item -verbose
+Print information about what @command{grmic} is doing.
+
+@item -d @var{directory}
+Put output files in @var{directory}. By default the files are put in
+the current working directory.
+
+@item -help
+Print a help message, then exit.
+
+@item -version
+Print version information, then exit.
+@end table
+
+@c man end
+
+
+@node Invoking gc-analyze
+@chapter Invoking gc-analyze
+
+@c man title gc-analyze Analyze Garbage Collector (GC) memory dumps
+
+@c man begin SYNOPSIS gc-analyze
+@command{gc-analyze} [@option{OPTION}] @dots{} [@var{file}]
+@ignore
+ [@option{-v}]
+ [@option{--verbose}]
+ [@option{-p} @var{tool-prefix}]
+ [@option{-d} @var{directory}]
+ [@option{--version}]
+ [@option{--help}]
+@end ignore
+@c man end
+
+@c man begin DESCRIPTION gc-analyze
+
+@command{gc-analyze} prints an analysis of a GC memory dump to
+standard out.
+
+The memory dumps may be created by calling
+@code{gnu.gcj.util.GCInfo.enumerate(String namePrefix)} from java
+code. A memory dump will be created on an out of memory condition if
+@code{gnu.gcj.util.GCInfo.setOOMDump(String namePrefix)} is called
+before the out of memory occurs.
+
+Running this program will create two files: @file{TestDump001} and
+@file{TestDump001.bytes}.
+
+@example
+import gnu.gcj.util.*;
+import java.util.*;
+
+public class GCDumpTest
+@{
+ static public void main(String args[])
+ @{
+ ArrayList<String> l = new ArrayList<String>(1000);
+
+ for (int i = 1; i < 1500; i++) @{
+ l.add("This is string #" + i);
+ @}
+ GCInfo.enumerate("TestDump");
+ @}
+@}
+@end example
+
+The memory dump may then be displayed by running:
+
+@example
+gc-analyze -v TestDump001
+@end example
+
+@c FIXME: Add real information here.
+@c This really isn't much more than the --help output.
+
+@c man end
+
+@c man begin OPTIONS gc-analyze
+
+@table @gcctabopt
+@item --verbose
+@itemx -v
+Verbose output.
+
+@item -p @var{tool-prefix}
+Prefix added to the names of the @command{nm} and @command{readelf} commands.
+
+@item -d @var{directory}
+Directory that contains the executable and shared libraries used when
+the dump was generated.
+
+@item --help
+Print a help message, then exit.
+
+@item --version
+Print version information, then exit.
+@end table
+
+@c man end
+
+@node About CNI
+@chapter About CNI
+
+This documents CNI, the Compiled Native Interface,
+which is is a convenient way to write Java native methods using C++.
+This is a more efficient, more convenient, but less portable
+alternative to the standard JNI (Java Native Interface).
+
+@menu
+* Basic concepts:: Introduction to using CNI@.
+* Packages:: How packages are mapped to C++.
+* Primitive types:: Handling primitive Java types in C++.
+* Reference types:: Handling Java reference types in C++.
+* Interfaces:: How Java interfaces map to C++.
+* Objects and Classes:: C++ and Java classes.
+* Class Initialization:: How objects are initialized.
+* Object allocation:: How to create Java objects in C++.
+* Memory allocation:: How to allocate and free memory.
+* Arrays:: Dealing with Java arrays in C++.
+* Methods:: Java methods in C++.
+* Strings:: Information about Java Strings.
+* Mixing with C++:: How CNI can interoperate with C++.
+* Exception Handling:: How exceptions are handled.
+* Synchronization:: Synchronizing between Java and C++.
+* Invocation:: Starting the Java runtime from C++.
+* Reflection:: Using reflection from C++.
+@end menu
+
+
+@node Basic concepts
+@section Basic concepts
+
+In terms of languages features, Java is mostly a subset
+of C++. Java has a few important extensions, plus a powerful standard
+class library, but on the whole that does not change the basic similarity.
+Java is a hybrid object-oriented language, with a few native types,
+in addition to class types. It is class-based, where a class may have
+static as well as per-object fields, and static as well as instance methods.
+Non-static methods may be virtual, and may be overloaded. Overloading is
+resolved at compile time by matching the actual argument types against
+the parameter types. Virtual methods are implemented using indirect calls
+through a dispatch table (virtual function table). Objects are
+allocated on the heap, and initialized using a constructor method.
+Classes are organized in a package hierarchy.
+
+All of the listed attributes are also true of C++, though C++ has
+extra features (for example in C++ objects may be allocated not just
+on the heap, but also statically or in a local stack frame). Because
+@command{gcj} uses the same compiler technology as G++ (the GNU
+C++ compiler), it is possible to make the intersection of the two
+languages use the same ABI (object representation and calling
+conventions). The key idea in CNI is that Java objects are C++
+objects, and all Java classes are C++ classes (but not the other way
+around). So the most important task in integrating Java and C++ is to
+remove gratuitous incompatibilities.
+
+You write CNI code as a regular C++ source file. (You do have to use
+a Java/CNI-aware C++ compiler, specifically a recent version of G++.)
+
+@noindent A CNI C++ source file must have:
+
+@example
+#include <gcj/cni.h>
+@end example
+
+@noindent and then must include one header file for each Java class it uses, e.g.:
+
+@example
+#include <java/lang/Character.h>
+#include <java/util/Date.h>
+#include <java/lang/IndexOutOfBoundsException.h>
+@end example
+
+@noindent These header files are automatically generated by @code{gcjh}.
+
+
+CNI provides some functions and macros to make using Java objects and
+primitive types from C++ easier. In general, these CNI functions and
+macros start with the @code{Jv} prefix, for example the function
+@code{JvNewObjectArray}. This convention is used to avoid conflicts
+with other libraries. Internal functions in CNI start with the prefix
+@code{_Jv_}. You should not call these; if you find a need to, let us
+know and we will try to come up with an alternate solution.
+
+
+@subsection Limitations
+
+Whilst a Java class is just a C++ class that doesn't mean that you are
+freed from the shackles of Java, a @acronym{CNI} C++ class must adhere to the
+rules of the Java programming language.
+
+For example: it is not possible to declare a method in a CNI class
+that will take a C string (@code{char*}) as an argument, or to declare a
+member variable of some non-Java datatype.
+
+
+@node Packages
+@section Packages
+
+The only global names in Java are class names, and packages. A
+@dfn{package} can contain zero or more classes, and also zero or more
+sub-packages. Every class belongs to either an unnamed package or a
+package that has a hierarchical and globally unique name.
+
+A Java package is mapped to a C++ @dfn{namespace}. The Java class
+@code{java.lang.String} is in the package @code{java.lang}, which is a
+sub-package of @code{java}. The C++ equivalent is the class
+@code{java::lang::String}, which is in the namespace @code{java::lang}
+which is in the namespace @code{java}.
+
+@noindent Here is how you could express this:
+
+@example
+(// @r{Declare the class(es), possibly in a header file:}
+namespace java @{
+ namespace lang @{
+ class Object;
+ class String;
+ ...
+ @}
+@}
+
+class java::lang::String : public java::lang::Object
+@{
+ ...
+@};
+@end example
+
+@noindent The @code{gcjh} tool automatically generates the necessary namespace
+declarations.
+
+
+@subsection Leaving out package names
+
+Always using the fully-qualified name of a java class can be
+tiresomely verbose. Using the full qualified name also ties the code
+to a single package making code changes necessary should the class
+move from one package to another. The Java @code{package} declaration
+specifies that the following class declarations are in the named
+package, without having to explicitly name the full package
+qualifiers. The @code{package} declaration can be
+followed by zero or more @code{import} declarations, which
+allows either a single class or all the classes in a package to be
+named by a simple identifier. C++ provides something similar with the
+@code{using} declaration and directive.
+
+@noindent In Java:
+
+@example
+import @var{package-name}.@var{class-name};
+@end example
+
+@noindent allows the program text to refer to @var{class-name} as a shorthand for
+the fully qualified name: @code{@var{package-name}.@var{class-name}}.
+
+
+@noindent To achieve the same effect C++, you have to do this:
+
+@example
+using @var{package-name}::@var{class-name};
+@end example
+
+
+@noindent Java can also cause imports on demand, like this:
+
+@example
+import @var{package-name}.*;
+@end example
+
+@noindent Doing this allows any class from the package @var{package-name} to be
+referred to only by its class-name within the program text.
+
+
+@noindent The same effect can be achieved in C++ like this:
+
+@example
+using namespace @var{package-name};
+@end example
+
+
+@node Primitive types
+@section Primitive types
+
+Java provides 8 @dfn{primitives} types which represent integers, floats,
+characters and booleans (and also the void type). C++ has its own
+very similar concrete types. Such types in C++ however are not always
+implemented in the same way (an int might be 16, 32 or 64 bits for example)
+so CNI provides a special C++ type for each primitive Java type:
+
+@multitable @columnfractions .20 .25 .60
+@item @strong{Java type} @tab @strong{C/C++ typename} @tab @strong{Description}
+@item @code{char} @tab @code{jchar} @tab 16 bit Unicode character
+@item @code{boolean} @tab @code{jboolean} @tab logical (true or false) values
+@item @code{byte} @tab @code{jbyte} @tab 8-bit signed integer
+@item @code{short} @tab @code{jshort} @tab 16 bit signed integer
+@item @code{int} @tab @code{jint} @tab 32 bit signed integer
+@item @code{long} @tab @code{jlong} @tab 64 bit signed integer
+@item @code{float} @tab @code{jfloat} @tab 32 bit IEEE floating point number
+@item @code{double} @tab @code{jdouble} @tab 64 bit IEEE floating point number
+@item @code{void} @tab @code{void} @tab no value
+@end multitable
+
+When referring to a Java type You should always use these C++ typenames (e.g.: @code{jint})
+to avoid disappointment.
+
+
+@subsection Reference types associated with primitive types
+
+In Java each primitive type has an associated reference type,
+e.g.: @code{boolean} has an associated @code{java.lang.Boolean.TYPE} class.
+In order to make working with such classes easier GCJ provides the macro
+@code{JvPrimClass}:
+
+@deffn macro JvPrimClass type
+Return a pointer to the @code{Class} object corresponding to the type supplied.
+
+@example
+JvPrimClass(void) @result{} java.lang.Void.TYPE
+@end example
+
+@end deffn
+
+
+@node Reference types
+@section Reference types
+
+A Java reference type is treated as a class in C++. Classes and
+interfaces are handled this way. A Java reference is translated to a
+C++ pointer, so for instance a Java @code{java.lang.String} becomes,
+in C++, @code{java::lang::String *}.
+
+CNI provides a few built-in typedefs for the most common classes:
+@multitable @columnfractions .30 .25 .60
+@item @strong{Java type} @tab @strong{C++ typename} @tab @strong{Description}
+@item @code{java.lang.Object} @tab @code{jobject} @tab Object type
+@item @code{java.lang.String} @tab @code{jstring} @tab String type
+@item @code{java.lang.Class} @tab @code{jclass} @tab Class type
+@end multitable
+@cindex jobject
+@cindex jstring
+@cindex jclass
+
+Every Java class or interface has a corresponding @code{Class}
+instance. These can be accessed in CNI via the static @code{class$}
+field of a class. The @code{class$} field is of type @code{Class}
+(and not @code{Class *}), so you will typically take the address of
+it.
+@cindex class$
+
+Here is how you can refer to the class of @code{String}, which in
+Java would be written @code{String.class}:
+
+@example
+using namespace java::lang;
+doSomething (&String::class$);
+@end example
+
+
+@node Interfaces
+@section Interfaces
+
+A Java class can @dfn{implement} zero or more
+@dfn{interfaces}, in addition to inheriting from
+a single base class.
+
+@acronym{CNI} allows CNI code to implement methods of interfaces.
+You can also call methods through interface references, with some
+limitations.
+
+@acronym{CNI} doesn't understand interface inheritance at all yet. So,
+you can only call an interface method when the declared type of the
+field being called matches the interface which declares that
+method. The workaround is to cast the interface reference to the right
+superinterface.
+
+For example if you have:
+
+@example
+interface A
+@{
+ void a();
+@}
+
+interface B extends A
+@{
+ void b();
+@}
+@end example
+
+and declare a variable of type @code{B} in C++, you can't call
+@code{a()} unless you cast it to an @code{A} first.
+
+@node Objects and Classes
+@section Objects and Classes
+
+@subsection Classes
+
+All Java classes are derived from @code{java.lang.Object}. C++ does
+not have a unique root class, but we use the C++ class
+@code{java::lang::Object} as the C++ version of the
+@code{java.lang.Object} Java class. All other Java classes are mapped
+into corresponding C++ classes derived from @code{java::lang::Object}.
+
+Interface inheritance (the @code{implements} keyword) is currently not
+reflected in the C++ mapping.
+
+
+@subsection Object fields
+
+Each object contains an object header, followed by the instance fields
+of the class, in order. The object header consists of a single
+pointer to a dispatch or virtual function table. (There may be extra
+fields @emph{in front of} the object, for example for memory
+management, but this is invisible to the application, and the
+reference to the object points to the dispatch table pointer.)
+
+The fields are laid out in the same order, alignment, and size as in
+C++. Specifically, 8-bit and 16-bit native types (@code{byte},
+@code{short}, @code{char}, and @code{boolean}) are @emph{not} widened
+to 32 bits. Note that the Java VM does extend 8-bit and 16-bit types
+to 32 bits when on the VM stack or temporary registers.
+
+If you include the @code{gcjh}-generated header for a
+class, you can access fields of Java classes in the @emph{natural}
+way. For example, given the following Java class:
+
+@example
+public class Int
+@{
+ public int i;
+ public Int (int i) @{ this.i = i; @}
+ public static Int zero = new Int(0);
+@}
+@end example
+
+you can write:
+
+@example
+#include <gcj/cni.h>;
+#include <Int>;
+
+Int*
+mult (Int *p, jint k)
+@{
+ if (k == 0)
+ return Int::zero; // @r{Static member access.}
+ return new Int(p->i * k);
+@}
+@end example
+
+
+@subsection Access specifiers
+
+CNI does not strictly enforce the Java access
+specifiers, because Java permissions cannot be directly mapped
+into C++ permission. Private Java fields and methods are mapped
+to private C++ fields and methods, but other fields and methods
+are mapped to public fields and methods.
+
+
+
+@node Class Initialization
+@section Class Initialization
+
+Java requires that each class be automatically initialized at the time
+of the first active use. Initializing a class involves
+initializing the static fields, running code in class initializer
+methods, and initializing base classes. There may also be
+some implementation specific actions, such as allocating
+@code{String} objects corresponding to string literals in
+the code.
+
+The GCJ compiler inserts calls to @code{JvInitClass} at appropriate
+places to ensure that a class is initialized when required. The C++
+compiler does not insert these calls automatically---it is the
+programmer's responsibility to make sure classes are initialized.
+However, this is fairly painless because of the conventions assumed by
+the Java system.
+
+First, @code{libgcj} will make sure a class is initialized before an
+instance of that object is created. This is one of the
+responsibilities of the @code{new} operation. This is taken care of
+both in Java code, and in C++ code. When G++ sees a @code{new} of a
+Java class, it will call a routine in @code{libgcj} to allocate the
+object, and that routine will take care of initializing the class.
+Note however that this does not happen for Java arrays; you must
+allocate those using the appropriate CNI function. It follows that
+you can access an instance field, or call an instance (non-static)
+method and be safe in the knowledge that the class and all of its base
+classes have been initialized.
+
+Invoking a static method is also safe. This is because the
+Java compiler adds code to the start of a static method to make sure
+the class is initialized. However, the C++ compiler does not
+add this extra code. Hence, if you write a native static method
+using CNI, you are responsible for calling @code{JvInitClass}
+before doing anything else in the method (unless you are sure
+it is safe to leave it out).
+
+Accessing a static field also requires the class of the
+field to be initialized. The Java compiler will generate code
+to call @code{JvInitClass} before getting or setting the field.
+However, the C++ compiler will not generate this extra code,
+so it is your responsibility to make sure the class is
+initialized before you access a static field from C++.
+
+
+@node Object allocation
+@section Object allocation
+
+New Java objects are allocated using a
+@dfn{class instance creation expression}, e.g.:
+
+@example
+new @var{Type} ( ... )
+@end example
+
+The same syntax is used in C++. The main difference is that
+C++ objects have to be explicitly deleted; in Java they are
+automatically deleted by the garbage collector.
+Using @acronym{CNI}, you can allocate a new Java object
+using standard C++ syntax and the C++ compiler will allocate
+memory from the garbage collector. If you have overloaded
+constructors, the compiler will choose the correct one
+using standard C++ overload resolution rules.
+
+@noindent For example:
+
+@example
+java::util::Hashtable *ht = new java::util::Hashtable(120);
+@end example
+
+
+@node Memory allocation
+@section Memory allocation
+
+When allocating memory in @acronym{CNI} methods it is best to handle
+out-of-memory conditions by throwing a Java exception. These
+functions are provided for that purpose:
+
+@deftypefun void* JvMalloc (jsize @var{size})
+Calls malloc. Throws @code{java.lang.OutOfMemoryError} if allocation
+fails.
+@end deftypefun
+
+@deftypefun void* JvRealloc (void* @var{ptr}, jsize @var{size})
+Calls realloc. Throws @code{java.lang.OutOfMemoryError} if
+reallocation fails.
+@end deftypefun
+
+@deftypefun void JvFree (void* @var{ptr})
+Calls free.
+@end deftypefun
+
+@node Arrays
+@section Arrays
+
+While in many ways Java is similar to C and C++, it is quite different
+in its treatment of arrays. C arrays are based on the idea of pointer
+arithmetic, which would be incompatible with Java's security
+requirements. Java arrays are true objects (array types inherit from
+@code{java.lang.Object}). An array-valued variable is one that
+contains a reference (pointer) to an array object.
+
+Referencing a Java array in C++ code is done using the
+@code{JArray} template, which as defined as follows:
+
+@example
+class __JArray : public java::lang::Object
+@{
+public:
+ int length;
+@};
+
+template<class T>
+class JArray : public __JArray
+@{
+ T data[0];
+public:
+ T& operator[](jint i) @{ return data[i]; @}
+@};
+@end example
+
+
+There are a number of @code{typedef}s which correspond to @code{typedef}s
+from the @acronym{JNI}. Each is the type of an array holding objects
+of the relevant type:
+
+@example
+typedef __JArray *jarray;
+typedef JArray<jobject> *jobjectArray;
+typedef JArray<jboolean> *jbooleanArray;
+typedef JArray<jbyte> *jbyteArray;
+typedef JArray<jchar> *jcharArray;
+typedef JArray<jshort> *jshortArray;
+typedef JArray<jint> *jintArray;
+typedef JArray<jlong> *jlongArray;
+typedef JArray<jfloat> *jfloatArray;
+typedef JArray<jdouble> *jdoubleArray;
+@end example
+
+
+@deftypemethod {template<class T>} T* elements (JArray<T> @var{array})
+This template function can be used to get a pointer to the elements of
+the @code{array}. For instance, you can fetch a pointer to the
+integers that make up an @code{int[]} like so:
+
+@example
+extern jintArray foo;
+jint *intp = elements (foo);
+@end example
+
+The name of this function may change in the future.
+@end deftypemethod
+
+
+@deftypefun jobjectArray JvNewObjectArray (jsize @var{length}, jclass @var{klass}, jobject @var{init})
+This creates a new array whose elements have reference type.
+@code{klass} is the type of elements of the array and
+@code{init} is the initial value put into every slot in the array.
+@end deftypefun
+
+@example
+using namespace java::lang;
+JArray<String *> *array
+ = (JArray<String *> *) JvNewObjectArray(length, &String::class$, NULL);
+@end example
+
+
+@subsection Creating arrays
+
+For each primitive type there is a function which can be used to
+create a new array of that type. The name of the function is of the
+form:
+
+@example
+JvNew@var{Type}Array
+@end example
+
+@noindent For example:
+
+@example
+JvNewBooleanArray
+@end example
+
+@noindent can be used to create an array of Java primitive boolean types.
+
+@noindent The following function definition is the template for all such functions:
+
+@deftypefun jbooleanArray JvNewBooleanArray (jint @var{length})
+Creates an array @var{length} indices long.
+@end deftypefun
+
+@deftypefun jsize JvGetArrayLength (jarray @var{array})
+Returns the length of the @var{array}.
+@end deftypefun
+
+
+@node Methods
+@section Methods
+
+Java methods are mapped directly into C++ methods.
+The header files generated by @code{gcjh}
+include the appropriate method definitions.
+Basically, the generated methods have the same names and
+@emph{corresponding} types as the Java methods,
+and are called in the natural manner.
+
+@subsection Overloading
+
+Both Java and C++ provide method overloading, where multiple
+methods in a class have the same name, and the correct one is chosen
+(at compile time) depending on the argument types.
+The rules for choosing the correct method are (as expected) more complicated
+in C++ than in Java, but given a set of overloaded methods
+generated by @code{gcjh} the C++ compiler will choose
+the expected one.
+
+Common assemblers and linkers are not aware of C++ overloading,
+so the standard implementation strategy is to encode the
+parameter types of a method into its assembly-level name.
+This encoding is called @dfn{mangling},
+and the encoded name is the @dfn{mangled name}.
+The same mechanism is used to implement Java overloading.
+For C++/Java interoperability, it is important that both the Java
+and C++ compilers use the @emph{same} encoding scheme.
+
+@subsection Static methods
+
+Static Java methods are invoked in @acronym{CNI} using the standard
+C++ syntax, using the @code{::} operator rather
+than the @code{.} operator.
+
+@noindent For example:
+
+@example
+jint i = java::lang::Math::round((jfloat) 2.3);
+@end example
+
+@noindent C++ method definition syntax is used to define a static native method.
+For example:
+
+@example
+#include <java/lang/Integer>
+java::lang::Integer*
+java::lang::Integer::getInteger(jstring str)
+@{
+ ...
+@}
+@end example
+
+
+@subsection Object Constructors
+
+Constructors are called implicitly as part of object allocation
+using the @code{new} operator.
+
+@noindent For example:
+
+@example
+java::lang::Integer *x = new java::lang::Integer(234);
+@end example
+
+Java does not allow a constructor to be a native method.
+This limitation can be coded round however because a constructor
+can @emph{call} a native method.
+
+
+@subsection Instance methods
+
+Calling a Java instance method from a C++ @acronym{CNI} method is done
+using the standard C++ syntax, e.g.:
+
+@example
+// @r{First create the Java object.}
+java::lang::Integer *x = new java::lang::Integer(234);
+// @r{Now call a method.}
+jint prim_value = x->intValue();
+if (x->longValue == 0)
+ ...
+@end example
+
+@noindent Defining a Java native instance method is also done the natural way:
+
+@example
+#include <java/lang/Integer.h>
+
+jdouble
+java::lang:Integer::doubleValue()
+@{
+ return (jdouble) value;
+@}
+@end example
+
+
+@subsection Interface methods
+
+In Java you can call a method using an interface reference. This is
+supported, but not completely. @xref{Interfaces}.
+
+
+
+
+@node Strings
+@section Strings
+
+@acronym{CNI} provides a number of utility functions for
+working with Java Java @code{String} objects.
+The names and interfaces are analogous to those of @acronym{JNI}.
+
+
+@deftypefun jstring JvNewString (const jchar* @var{chars}, jsize @var{len})
+Returns a Java @code{String} object with characters from the array of
+Unicode characters @var{chars} up to the index @var{len} in that array.
+@end deftypefun
+
+@deftypefun jstring JvNewStringLatin1 (const char* @var{bytes}, jsize @var{len})
+Returns a Java @code{String} made up of @var{len} bytes from @var{bytes}.
+@end deftypefun
+
+
+@deftypefun jstring JvNewStringLatin1 (const char* @var{bytes})
+As above but the length of the @code{String} is @code{strlen(@var{bytes})}.
+@end deftypefun
+
+@deftypefun jstring JvNewStringUTF (const char* @var{bytes})
+Returns a @code{String} which is made up of the UTF encoded characters
+present in the C string @var{bytes}.
+@end deftypefun
+
+@deftypefun jchar* JvGetStringChars (jstring @var{str})
+Returns a pointer to an array of characters making up the @code{String} @var{str}.
+@end deftypefun
+
+@deftypefun int JvGetStringUTFLength (jstring @var{str})
+Returns the number of bytes required to encode the contents of the
+@code{String} @var{str} in UTF-8.
+@end deftypefun
+
+@deftypefun jsize JvGetStringUTFRegion (jstring @var{str}, jsize @var{start}, jsize @var{len}, char* @var{buf})
+Puts the UTF-8 encoding of a region of the @code{String} @var{str} into
+the buffer @code{buf}. The region to fetch is marked by @var{start} and @var{len}.
+
+Note that @var{buf} is a buffer, not a C string. It is @emph{not}
+null terminated.
+@end deftypefun
+
+
+@node Mixing with C++
+@section Interoperating with C/C++
+
+Because @acronym{CNI} is designed to represent Java classes and methods it
+cannot be mixed readily with C/C++ types.
+
+One important restriction is that Java classes cannot have non-Java
+type instance or static variables and cannot have methods which take
+non-Java types as arguments or return non-Java types.
+
+@noindent None of the following is possible with CNI:
+
+@example
+
+class ::MyClass : public java::lang::Object
+@{
+ char* variable; // @r{char* is not a valid Java type.}
+@}
+
+
+uint
+::SomeClass::someMethod (char *arg)
+@{
+ .
+ .
+ .
+@} // @r{@code{uint} is not a valid Java type, neither is @code{char*}}
+@end example
+
+@noindent Of course, it is ok to use C/C++ types within the scope of a method:
+
+
+@example
+jint
+::SomeClass::otherMethod (jstring str)
+@{
+ char *arg = ...
+ .
+ .
+ .
+@}
+@end example
+
+@subsection RawData
+
+The above restriction can be problematic, so @acronym{CNI} includes the
+@code{gnu.gcj.RawData} class. The @code{RawData} class is a
+@dfn{non-scanned reference} type. In other words variables declared
+of type @code{RawData} can contain any data and are not checked by the
+compiler or memory manager in any way.
+
+This means that you can put C/C++ data structures (including classes)
+in your @acronym{CNI} classes, as long as you use the appropriate cast.
+
+@noindent Here are some examples:
+
+@example
+
+class ::MyClass : public java::lang::Object
+@{
+ gnu.gcj.RawData string;
+
+ MyClass ();
+ gnu.gcj.RawData getText ();
+ void printText ();
+@}
+
+::MyClass::MyClass ()
+@{
+ char* text = ...
+ string = text;
+@}
+
+gnu.gcj.RawData
+::MyClass::getText ()
+@{
+ return string;
+@}
+
+void
+::MyClass::printText ()
+@{
+ printf("%s\n", (char*) string);
+@}
+@end example
+
+
+@subsection RawDataManaged
+
+@code{gnu.gcj.RawDataManaged} is another type used to indicate special data used
+by native code. Unlike the @code{RawData} type, fields declared as
+@code{RawDataManaged} will be "marked" by the memory manager and
+considered for garbage collection.
+
+Native data which is allocated using CNI's @code{JvAllocBytes()}
+function and stored in a @code{RawDataManaged} will be automatically
+freed when the Java object it is associated with becomes unreachable.
+
+@subsection Native memory allocation
+
+@deftypefun void* JvAllocBytes (jsize @var{size})
+Allocates @var{size} bytes from the heap. The memory returned is zeroed.
+This memory is not scanned for pointers by the garbage collector, but will
+be freed if no references to it are discovered.
+
+This function can be useful if you need to associate some native data with a
+Java object. Using a CNI's special @code{RawDataManaged} type, native data
+allocated with @code{JvAllocBytes} will be automatically freed when the Java
+object itself becomes unreachable.
+@end deftypefun
+
+@subsection Posix signals
+
+On Posix based systems the @code{libgcj} library uses several signals
+internally. @acronym{CNI} code should not attempt to use the same
+signals as doing so may cause @code{libgcj} and/or the @acronym{CNI}
+code to fail.
+
+SIGSEGV is used on many systems to generate
+@code{NullPointerExceptions}. SIGCHLD is used internally by
+@code{Runtime.exec()}. Several other signals (that vary from platform to
+platform) can be used by the memory manager and by
+@code{Thread.interrupt()}.
+
+@node Exception Handling
+@section Exception Handling
+
+While C++ and Java share a common exception handling framework,
+things are not yet perfectly integrated. The main issue is that the
+run-time type information facilities of the two
+languages are not integrated.
+
+Still, things work fairly well. You can throw a Java exception from
+C++ using the ordinary @code{throw} construct, and this
+exception can be caught by Java code. Similarly, you can catch an
+exception thrown from Java using the C++ @code{catch}
+construct.
+
+@noindent Here is an example:
+
+@example
+if (i >= count)
+ throw new java::lang::IndexOutOfBoundsException();
+@end example
+
+Normally, G++ will automatically detect when you are writing C++
+code that uses Java exceptions, and handle them appropriately.
+However, if C++ code only needs to execute destructors when Java
+exceptions are thrown through it, GCC will guess incorrectly. Sample
+problematic code:
+
+@example
+struct S @{ ~S(); @};
+
+extern void bar(); // @r{Is implemented in Java and may throw exceptions.}
+
+void foo()
+@{
+ S s;
+ bar();
+@}
+@end example
+
+The usual effect of an incorrect guess is a link failure, complaining of
+a missing routine called @code{__gxx_personality_v0}.
+
+You can inform the compiler that Java exceptions are to be used in a
+translation unit, irrespective of what it might think, by writing
+@code{#pragma GCC java_exceptions} at the head of the
+file. This @code{#pragma} must appear before any
+functions that throw or catch exceptions, or run destructors when
+exceptions are thrown through them.
+
+@node Synchronization
+@section Synchronization
+
+Each Java object has an implicit monitor.
+The Java VM uses the instruction @code{monitorenter} to acquire
+and lock a monitor, and @code{monitorexit} to release it.
+
+The corresponding CNI macros are @code{JvMonitorEnter} and
+@code{JvMonitorExit} (JNI has similar methods @code{MonitorEnter}
+and @code{MonitorExit}).
+
+
+The Java source language does not provide direct access to these primitives.
+Instead, there is a @code{synchronized} statement that does an
+implicit @code{monitorenter} before entry to the block,
+and does a @code{monitorexit} on exit from the block.
+Note that the lock has to be released even when the block is abnormally
+terminated by an exception, which means there is an implicit
+@code{try finally} surrounding synchronization locks.
+
+From C++, it makes sense to use a destructor to release a lock.
+@acronym{CNI} defines the following utility class:
+
+@example
+class JvSynchronize() @{
+ jobject obj;
+ JvSynchronize(jobject o) @{ obj = o; JvMonitorEnter(o); @}
+ ~JvSynchronize() @{ JvMonitorExit(obj); @}
+@};
+@end example
+
+So this Java code:
+
+@example
+synchronized (OBJ)
+@{
+ CODE
+@}
+@end example
+
+@noindent might become this C++ code:
+
+@example
+@{
+ JvSynchronize dummy (OBJ);
+ CODE;
+@}
+@end example
+
+Java also has methods with the @code{synchronized} attribute.
+This is equivalent to wrapping the entire method body in a
+@code{synchronized} statement.
+(Alternatively, an implementation could require the caller to do
+the synchronization. This is not practical for a compiler, because
+each virtual method call would have to test at run-time if
+synchronization is needed.) Since in @command{gcj}
+the @code{synchronized} attribute is handled by the
+method implementation, it is up to the programmer
+of a synchronized native method to handle the synchronization
+(in the C++ implementation of the method).
+In other words, you need to manually add @code{JvSynchronize}
+in a @code{native synchronized} method.
+
+@node Invocation
+@section Invocation
+
+CNI permits C++ applications to make calls into Java classes, in addition to
+allowing Java code to call into C++. Several functions, known as the
+@dfn{invocation API}, are provided to support this.
+
+@deftypefun jint JvCreateJavaVM (JvVMInitArgs* @var{vm_args})
+
+Initializes the Java runtime. This function performs essential initialization
+of the threads interface, garbage collector, exception handling and other key
+aspects of the runtime. It must be called once by an application with
+a non-Java @code{main()} function, before any other Java or CNI calls are made.
+It is safe, but not recommended, to call @code{JvCreateJavaVM()} more than
+once provided it is only called from a single thread.
+The @var{vmargs} parameter can be used to specify initialization parameters
+for the Java runtime. It may be @code{NULL}.
+
+JvVMInitArgs represents a list of virtual machine initialization
+arguments. @code{JvCreateJavaVM()} ignores the version field.
+
+@example
+typedef struct JvVMOption
+@{
+ // a VM initialization option
+ char* optionString;
+ // extra information associated with this option
+ void* extraInfo;
+@} JvVMOption;
+
+typedef struct JvVMInitArgs
+@{
+ // for compatibility with JavaVMInitArgs
+ jint version;
+
+ // number of VM initialization options
+ jint nOptions;
+
+ // an array of VM initialization options
+ JvVMOption* options;
+
+ // true if the option parser should ignore unrecognized options
+ jboolean ignoreUnrecognized;
+@} JvVMInitArgs;
+@end example
+
+@code{JvCreateJavaVM()} returns @code{0} upon success, or @code{-1} if
+the runtime is already initialized.
+
+@emph{Note:} In GCJ 3.1, the @code{vm_args} parameter is ignored. It
+is recognized and used as of release 4.0.
+@end deftypefun
+
+@deftypefun java::lang::Thread* JvAttachCurrentThread (jstring @var{name}, java::lang::ThreadGroup* @var{group})
+Registers an existing thread with the Java runtime. This must be called once
+from each thread, before that thread makes any other Java or CNI calls. It
+must be called after @code{JvCreateJavaVM}.
+@var{name} specifies a name for the thread. It may be @code{NULL}, in which
+case a name will be generated.
+@var{group} is the ThreadGroup in which this thread will be a member. If it
+is @code{NULL}, the thread will be a member of the main thread group.
+The return value is the Java @code{Thread} object that represents the thread.
+It is safe to call @code{JvAttachCurrentThread()} more than once from the same
+thread. If the thread is already attached, the call is ignored and the current
+thread object is returned.
+@end deftypefun
+
+@deftypefun jint JvDetachCurrentThread ()
+Unregisters a thread from the Java runtime. This should be called by threads
+that were attached using @code{JvAttachCurrentThread()}, after they have
+finished making calls to Java code. This ensures that any resources associated
+with the thread become eligible for garbage collection.
+This function returns @code{0} upon success, or @code{-1} if the current thread
+is not attached.
+@end deftypefun
+
+@subsection Handling uncaught exceptions
+
+If an exception is thrown from Java code called using the invocation API, and
+no handler for the exception can be found, the runtime will abort the
+application. In order to make the application more robust, it is recommended
+that code which uses the invocation API be wrapped by a top-level try/catch
+block that catches all Java exceptions.
+
+@subsection Example
+
+The following code demonstrates the use of the invocation API. In this
+example, the C++ application initializes the Java runtime and attaches
+itself. The @code{java.lang.System} class is initialized in order to
+access its @code{out} field, and a Java string is printed. Finally, the thread
+is detached from the runtime once it has finished making Java calls. Everything
+is wrapped with a try/catch block to provide a default handler for any uncaught
+exceptions.
+
+The example can be compiled with @command{c++ -c test.cc; gcj test.o}.
+
+@example
+// test.cc
+#include <gcj/cni.h>
+#include <java/lang/System.h>
+#include <java/io/PrintStream.h>
+#include <java/lang/Throwable.h>
+
+int main(int argc, char *argv[])
+@{
+ using namespace java::lang;
+
+ try
+ @{
+ JvCreateJavaVM(NULL);
+ JvAttachCurrentThread(NULL, NULL);
+
+ String *message = JvNewStringLatin1("Hello from C++");
+ JvInitClass(&System::class$);
+ System::out->println(message);
+
+ JvDetachCurrentThread();
+ @}
+ catch (Throwable *t)
+ @{
+ System::err->println(JvNewStringLatin1("Unhandled Java exception:"));
+ t->printStackTrace();
+ @}
+@}
+@end example
+
+@node Reflection
+@section Reflection
+
+Reflection is possible with CNI code, it functions similarly to how it
+functions with JNI@.
+
+@c clean this up... I mean, what are the types jfieldID and jmethodID in JNI?
+The types @code{jfieldID} and @code{jmethodID}
+are as in JNI@.
+
+@noindent The functions:
+
+@itemize
+@item @code{JvFromReflectedField},
+@item @code{JvFromReflectedMethod},
+@item @code{JvToReflectedField}
+@item @code{JvToFromReflectedMethod}
+@end itemize
+
+@noindent will be added shortly, as will other functions corresponding to JNI@.
+
+
+@node System properties
+@chapter System properties
+
+The runtime behavior of the @code{libgcj} library can be modified by setting
+certain system properties. These properties can be compiled into the program
+using the @code{-D@var{name}[=@var{value}]} option to @command{gcj} or by
+setting them explicitly in the program by calling the
+@code{java.lang.System.setProperty()} method. Some system properties are only
+used for informational purposes (like giving a version number or a user name).
+A program can inspect the current value of a property by calling the
+@code{java.lang.System.getProperty()} method.
+
+@menu
+* Standard Properties:: Standard properties supported by @code{libgcj}
+* GNU Classpath Properties:: Properties found in Classpath based libraries
+* libgcj Runtime Properties:: Properties specific to @code{libgcj}
+@end menu
+
+@node Standard Properties
+@section Standard Properties
+
+The following properties are normally found in all implementations of the core
+libraries for the Java language.
+
+@table @gcctabopt
+
+@item java.version
+The @code{libgcj} version number.
+
+@item java.vendor
+Set to @samp{The Free Software Foundation, Inc.}
+
+@item java.vendor.url
+Set to @uref{http://gcc.gnu.org/java/}.
+
+@item java.home
+The directory where @code{gcj} was installed. Taken from the @code{--prefix}
+option given to @command{configure}.
+
+@item java.class.version
+The class format version number supported by the libgcj byte code interpreter.
+(Currently @samp{46.0})
+
+@item java.vm.specification.version
+The Virtual Machine Specification version implemented by @code{libgcj}.
+(Currently @samp{1.0})
+
+@item java.vm.specification.vendor
+The name of the Virtual Machine specification designer.
+
+@item java.vm.specification.name
+The name of the Virtual Machine specification
+(Set to @samp{Java Virtual Machine Specification}).
+
+@item java.vm.version
+The @command{gcj} version number.
+
+@item java.vm.vendor
+Set to @samp{The Free Software Foundation, Inc.}
+
+@item java.vm.name
+Set to @samp{GNU libgcj}.
+
+@item java.specification.version
+The Runtime Environment specification version implemented by @code{libgcj}.
+(Currently set to @samp{1.3})
+
+@item java.specification.vendor
+The Runtime Environment specification designer.
+
+@item java.specification.name
+The name of the Runtime Environment specification
+(Set to @samp{Java Platform API Specification}).
+
+@item java.class.path
+The paths (jar files, zip files and directories) used for finding class files.
+
+@item java.library.path
+Directory path used for finding native libraries.
+
+@item java.io.tmpdir
+The directory used to put temporary files in.
+
+@item java.compiler
+Name of the Just In Time compiler to use by the byte code interpreter.
+Currently not used in @code{libgcj}.
+
+@item java.ext.dirs
+Directories containing jar files with extra libraries. Will be used when
+resolving classes.
+
+@item java.protocol.handler.pkgs
+A @samp{|} separated list of package names that is used to find classes that
+implement handlers for @code{java.net.URL}.
+
+@item java.rmi.server.codebase
+A list of URLs that is used by the @code{java.rmi.server.RMIClassLoader}
+to load classes from.
+
+@item jdbc.drivers
+A list of class names that will be loaded by the @code{java.sql.DriverManager}
+when it starts up.
+
+@item file.separator
+The separator used in when directories are included in a filename
+(normally @samp{/} or @samp{\} ).
+
+@item file.encoding
+The default character encoding used when converting platform native files to
+Unicode (usually set to @samp{8859_1}).
+
+@item path.separator
+The standard separator used when a string contains multiple paths
+(normally @samp{:} or @samp{;}), the string is usually not a valid character
+to use in normal directory names.)
+
+@item line.separator
+The default line separator used on the platform (normally @samp{\n}, @samp{\r}
+or a combination of those two characters).
+
+@item policy.provider
+The class name used for the default policy provider returned by
+@code{java.security.Policy.getPolicy}.
+
+@item user.name
+The name of the user running the program. Can be the full name, the login name
+or empty if unknown.
+
+@item user.home
+The default directory to put user specific files in.
+
+@item user.dir
+The current working directory from which the program was started.
+
+@item user.language
+The default language as used by the @code{java.util.Locale} class.
+
+@item user.region
+The default region as used by the @code{java.util.Local} class.
+
+@item user.variant
+The default variant of the language and region local used.
+
+@item user.timezone
+The default timezone as used by the @code{java.util.TimeZone} class.
+
+@item os.name
+The operating system/kernel name that the program runs on.
+
+@item os.arch
+The hardware that we are running on.
+
+@item os.version
+The version number of the operating system/kernel.
+
+@item awt.appletWarning
+The string to display when an untrusted applet is displayed.
+Returned by @code{java.awt.Window.getWarningString()} when the window is
+``insecure''.
+
+@item awt.toolkit
+The class name used for initializing the default @code{java.awt.Toolkit}.
+Defaults to @code{gnu.awt.gtk.GtkToolkit}.
+
+@item http.proxyHost
+Name of proxy host for http connections.
+
+@item http.proxyPort
+Port number to use when a proxy host is in use.
+
+@end table
+
+@node GNU Classpath Properties
+@section GNU Classpath Properties
+
+@code{libgcj} is based on the GNU Classpath (Essential Libraries for Java) a
+GNU project to create free core class libraries for use with virtual machines
+and compilers for the Java language. The following properties are common to
+libraries based on GNU Classpath.
+
+@table @gcctabopt
+
+@item gcj.dumpobject
+Enables printing serialization debugging by the @code{java.io.ObjectInput} and
+@code{java.io.ObjectOutput} classes when set to something else then the empty
+string. Only used when running a debug build of the library.
+
+@item gnu.classpath.vm.shortname
+This is a succinct name of the virtual machine. For @code{libgcj},
+this will always be @samp{libgcj}.
+
+@item gnu.classpath.home.url
+A base URL used for finding system property files (e.g.,
+@file{classpath.security}). By default this is a @samp{file:} URL
+pointing to the @file{lib} directory under @samp{java.home}.
+
+@end table
+
+@node libgcj Runtime Properties
+@section libgcj Runtime Properties
+
+The following properties are specific to the @code{libgcj} runtime and will
+normally not be found in other core libraries for the java language.
+
+@table @gcctabopt
+
+@item java.fullversion
+The combination of @code{java.vm.name} and @code{java.vm.version}.
+
+@item java.vm.info
+Same as @code{java.fullversion}.
+
+@item impl.prefix
+Used by the @code{java.net.DatagramSocket} class when set to something else
+then the empty string. When set all newly created @code{DatagramSocket}s will
+try to load a class @code{java.net.[impl.prefix]DatagramSocketImpl} instead of
+the normal @code{java.net.PlainDatagramSocketImpl}.
+
+@item gnu.gcj.progname
+The class or binary name that was used to invoke the program. This will be
+the name of the "main" class in the case where the @code{gij} front end is
+used, or the program binary name in the case where an application is compiled
+to a native binary.
+
+@item gnu.gcj.user.realname
+The real name of the user, as taken from the password file. This may
+not always hold only the user's name (as some sites put extra
+information in this field). Also, this property is not available on
+all platforms.
+
+@item gnu.gcj.runtime.NameFinder.use_addr2line
+Whether an external process, @command{addr2line}, should be used to determine
+line number information when tracing the stack. Setting this to @code{false}
+may suppress line numbers when printing stack traces and when using
+the java.util.logging infrastructure. However, performance may improve
+significantly for applications that print stack traces or make logging calls
+frequently.
+
+@item gnu.gcj.runtime.NameFinder.show_raw
+Whether the address of a stack frame should be printed when the line
+number is unavailable. Setting this to @code{true} will cause the name
+of the object and the offset within that object to be printed when no
+line number is available. This allows for off-line decoding of
+stack traces if necessary debug information is available. The default
+is @code{false}, no raw addresses are printed.
+
+@item gnu.gcj.runtime.NameFinder.remove_unknown
+Whether stack frames for non-java code should be included in a stack
+trace. The default value is @code{true}, stack frames for non-java
+code are suppressed. Setting this to @code{false} will cause any
+non-java stack frames to be printed in addition to frames for the java
+code.
+
+@item gnu.gcj.runtime.VMClassLoader.library_control
+This controls how shared libraries are automatically loaded by the
+built-in class loader. If this property is set to @samp{full}, a full
+search is done for each requested class. If this property is set to
+@samp{cache}, then any failed lookups are cached and not tried again.
+If this property is set to @samp{never} (the default), then lookups
+are never done. For more information, @xref{Extensions}.
+
+@item gnu.gcj.runtime.endorsed.dirs
+This is like the standard @code{java.endorsed.dirs}, property, but
+specifies some extra directories which are searched after the standard
+endorsed directories. This is primarily useful for telling
+@code{libgcj} about additional libraries which are ordinarily
+incorporated into the JDK, and which should be loaded by the bootstrap
+class loader, but which are not yet part of @code{libgcj} itself for
+some reason.
+
+@item gnu.gcj.jit.compiler
+@c FIXME we should probably have a whole node on this...
+This is the full path to @command{gcj} executable which should be
+used to compile classes just-in-time when
+@code{ClassLoader.defineClass} is called. If not set, @command{gcj}
+will not be invoked by the runtime; this can also be controlled via
+@code{Compiler.disable}.
+
+@item gnu.gcj.jit.options
+This is a space-separated string of options which should be passed to
+@command{gcj} when in JIT mode. If not set, a sensible default is
+chosen.
+
+@item gnu.gcj.jit.cachedir
+This is the directory where cached shared library files are
+stored. If not set, JIT compilation is disabled. This should never
+be set to a directory that is writable by any other user.
+
+@item gnu.gcj.precompiled.db.path
+This is a sequence of file names, each referring to a file created by
+@command{gcj-dbtool}. These files will be used by @code{libgcj} to
+find shared libraries corresponding to classes that are loaded from
+bytecode. @code{libgcj} often has a built-in default database; it
+can be queried using @code{gcj-dbtool -p}.
+
@end table
@node Resources
@chapter Resources
-While writing @code{gcj} and @code{libgcj} we have, of course, relied
+While writing @command{gcj} and @code{libgcj} we have, of course, relied
heavily on documentation from Sun Microsystems. In particular we have
used The Java Language Specification (both first and second editions),
the Java Class Libraries (volumes one and two), and the Java Virtual
Machine Specification. In addition we've used the online documentation
at @uref{http://java.sun.com/}.
-The current @code{gcj} home page is
+The current @command{gcj} home page is
@uref{http://gcc.gnu.org/java/}.
For more information on gcc, see @uref{http://gcc.gnu.org/}.
because the JCK is not free. See
@uref{http://sources.redhat.com/mauve/} for more information.
+
+@node Index
+@unnumbered Index
+
+@printindex cp
+
@bye
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