gij − GNU interpreter for Java bytecode


gij [ OPTION ] ... JARFILE [ ARGS ...]

gij [−jar] [ OPTION ] ... CLASS [ ARGS ...]
[−cp path] [−classpath path]
[−ms=number] [−mx=number]
[−Xargument] [−verbose] [−verbose:class]
[−−showversion] [−−version] [−−help][−?]


"gij" is a Java bytecode interpreter included with "libgcj". "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 gcj.

The primary argument to "gij" is the name of a class or, with "−jar", a jar file. Options before this argument are interpreted by "gij"; remaining options are passed to the interpreted program.

If a class name is specified and this class does not have a "main" method with the appropriate signature (a "static void" method with a "String[]" as its sole argument), then "gij" will print an error and exit.

If a jar file is specified then "gij" will use information in it to determine which class’ "main" method will be invoked.

"gij" will invoke the "main" method with all the remaining command-line options.

Note that "gij" is not limited to interpreting code. Because "libgcj" includes a class loader which can dynamically load shared objects, it is possible to give "gij" the name of a class which has been compiled and put into a shared library on the class path.


−cp path

Set the initial class path. The class path is used for finding class and resource files. If specified, this option overrides the "CLASSPATH" environment variable. Note that this option is ignored if "−jar" is used.


This defines a system property named name with value value. If value is not specified then it defaults to the empty string. These system properties are initialized at the program’s startup and can be retrieved at runtime using the "java.lang.System.getProperty" method.


Equivalent to "−Xms".


Equivalent to "−Xmx".


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.



Supplying "−X" by itself will cause "gij" to list all the supported "−X" options. Currently these options are supported:

Set the initial heap size.


Set the maximum heap size.


Set the thread stack size.

Unrecognized "−X" options are ignored, for compatibility with other runtimes.


This indicates that the name passed to "gij" should be interpreted as the name of a jar file, not a class.



Print help, then exit.


Print version number and continue.


Print detailed version information, then exit.


Print version number, then exit.


Each time a class is initialized, print a short message on standard error.

"gij" also recognizes and ignores the following options, for compatibility with existing application launch scripts: "−client", "−server", "−hotspot", "−jrockit", "−agentlib", "−agentpath", "−debug", "−d32", "−d64", "−javaagent", "−noclassgc", "−verify", and "−verifyremote".


gcc(1), gcj(1), gcjh(1), jcf−dump(1), gfdl(7), and the Info entries for gcj and gcc.


Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010 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 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, 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 man page gfdl(7).

(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.


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