'\" t
.\" @(#)java.1 1.9 98/06/30 SMI;
.\" Copyright (c) 1996 Sun Microsystems, Inc.
.\" All Rights Reserved.
'\"macro stdmacro
.TH java 1 "20 May 1998"
.SH NAME
java \- Java interpreter
.\" 
.\"  This document was created by saving an HTML file as text
.\"  from the JavaSoft web site:
.\" 
.\" http://www.javasoft.com:80/products/jdk/1.1/docs/tooldocs/solaris/index.html
.\" 
.\"  and adding appropriate troff macros.  Because the JavaSoft web site 
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.SH SYNOPSIS
.B java 
[ 
.BR \-cs " | "  \-checksource
] [
.BI \-classpath path
]
.if n .ti +5n
[
\f3\-DpropertyName\f1=\f2newValue\f1
] 
.if t .ti +5n
[
.B  \-debug 
] [
.B  \-fullversion
] 
.if n .ti +5n
[
.B  \-help
] [
.BI \-ms x
] [
.BI \-mx x
] [
.B \-noasyncgc
] 
.ti +5n
[
.B \-noclassgc
] [
.B \-noverify
] [
.BI \-oss x
] [
.B  \-prof
] 
.if n .ti +5n
[
.BI \-prof file
] [
.BI \-ss x
] [
.B \-t
] 
.if t .ti +5n
[
.BR \-v " | " \-verbose 
]
.if n .ti +5n
[
.B \-verbosegc
] [
.B \-verify
] [ 
.B \-verifyremote
] 
.if n .ti +5n
[ 
.B  \-version
]
.if t .ti +5n
.I classname <args>
.br
.B java_g 
[ 
.BR \-cs " | "  \-checksource
] [
.BI \-classpath path
]
.if n .ti +5n
[
\f3\-DpropertyName\f1=\f2newValue\f1
] 
.if t .ti +5n
[
.B  \-debug 
] [
.B  \-fullversion
] 
.if n .ti +5n
[
.B  \-help
] [
.BI \-ms x
] [
.BI \-mx x
] [
.B \-noasyncgc
] 
.ti +5n
[
.B \-noclassgc
] [
.B \-noverify
] [
.BI \-oss x
] [
.B  \-prof
] 
.if n .ti +5n
[
.BI \-prof file
] [
.BI \-ss x
] [
.B \-t
] 
.if t .ti +5n
[
.BR \-v " | " \-verbose 
]
.if n .ti +5n
[
.B \-verbosegc
] [
.B \-verify
] [ 
.B \-verifyremote
] 
.if n .ti +5n
[ 
.B  \-version
]
.if t .ti +5n
.I classname <args>
.SH DESCRIPTION
.IX "Java interpreter" "" "Java interpreter \(em \fLjava\fP"
.IX "java" "" "\fLjava\fP \(em Java interpreter"
The
.B java
command executes Java\(tm bytecodes created by the Java
compiler, \f3javac\f1.
The JIT (just in time) compiler compiles these
bytecodes into machine instructions by default
in the Solaris Java VM when using \f3java\f1.
(To disable this default, see the
.B USAGE
section below.)
.LP 
The
.I classname
argument is the name of the class to be
executed and
must be fully qualified by including the
package in the name, for example:
.sp 1n
.RS
.B example% java java.lang.String
.RE
.sp 1n
Note that any arguments that appear after
.I classname
on the
command line are passed to the 
.B main(\|) 
method of
the class.
.LP 
The bytecodes for the class are put in a file called
.I classname.class
by compiling the
corresponding source file with
.B javac.
All Java bytecode
files end with the filename extension
.B .class
which the
compiler automatically adds when the class is compiled.
The
.I classname
argument
must contain a 
.B main(\|) 
method defined as follows:
.sp 1n
.RS
.ft3
.nf 
class Aclass {
	public static void main(String argv[]){
			. . .
	}
}
.fi
.ft1
.sp 1n
.RE
The
.B java
command
executes the 
.B main(\|) 
method and exits unless 
.B main(\|) 
creates one or more threads. 
In this case,
.B java
doesn't exit until the last thread exits.
.LP
When defining classes, specify their
location with the
.SB CLASSPATH
environment variable, which
consists of a
colon-separated list of directories that specifies the path.
For example:
.sp 1n
.RS
.B .:/home/avh/classes
.RE
.sp 1n
Note that the system always appends the location of the
system classes onto the end of the class path unless using
the 
.BR \-classpath 
option to specify a path.
.LP 
Ordinarily, compile source files with
.BR  javac ,
then run the
program using
.BR java .
However,
.B java
can be used to compile and
run programs when the 
.BR \- cs 
option is used. As each class is
loaded, the modification date is compared to that
of the class source file. If the source has been
modified more recently, it is recompiled and the new
bytecode file is loaded. 
The
.B java 
command
repeats this procedure until
all the classes are correctly compiled and loaded.
.LP 
The interpreter determines whether a class is legitimate
by verification that ensures that
the bytecodes, being interpreted, do not violate 
language constraints.
.LP 
.B java_g
is a non-optimized version of 
.B java 
for use
with debuggers like
.BR jdb (1).
When using
.B  java_g
to run a program that loads a shared library, you must supply
a debug version of the library.  You can create a debug
version of a library by simply appending "\f3_g\f1"
to the name of the file.  For example, if the library was
.BR  libhello.so ,
the debug version of the library would be named
.BR  libhello.so_g .
.SH OPTIONS
.TP 15
.BR  \-cs " | " \-checksource
When a compiled class is loaded, this option causes the
modification time of the class bytecode file to be
compared to that of the class source file. 
If the
source has been modified more recently, it is
recompiled and the new bytecode file is loaded.
.TP 15 
.BI \-classpath path
Specifies the
.I path
that
.B java
uses to look up classes.
This overrides the default or 
.SB CLASSPATH
environment
variable, if it is set. Directories are separated by
colons. Thus, the general format for
.I path
is:
.RS 20
.sp 1n
.B .:<your_path>
.sp 1n
.RE
.RS 15
For example:
.RE
.sp 1n
.RS 20
.B .:/home/avh/classes:/usr/local/java/classes
.RE
.sp 1n
.TP 15 
\f3\-DpropertyName\f1=\f2newValue\f1
Redefines a property value where
.I propertyName
is the name of
the property value to be changed and
.I newValue
is the value. For example,
this command line
.sp 1n
.RS 20
.B example% java -Dawt.button.color=green ...
.RE
.sp 1n
.RS 15
sets the value of the property 
.B awt.button.color 
to green.
.B java
accepts any number of 
.B \-D 
options on the
command line.
.RE
.TP 15
.B \-debug
Allows the Java debugger - 
.BR jdb (1)
- to attach itself to this
.B java 
session. When 
.B  \-debug 
is specified on the command
line 
.B java 
displays a password that must be used when
starting the debugging session.
.TP 15
.B  \-fullversion
Displays full version information.
.TP 15
.B \-help
Displays a usage message.
.TP 15
.BI \-ms x
Sets the startup size of the memory allocation pool
(the garbage collected heap) to
.I x.
The default is 4
megabytes of memory.
.I x
must be > 1000 bytes
and must be less than or equal
to the maximum memory size (specified with the
.B  \-mx
option).
.sp 1n
By default,
.I x
is measured in bytes. To specify
.I x
in either kilobytes or megabytes, append 
"k" for kilobytes or "m" for
megabytes.
.br
.ne 6
.TP 15
.BI \-mx x
Sets the maximum size of the memory allocation pool
(the garbage collected heap) to
.I x.
The default is 16
megabytes of memory.
.I x
must be > 1000 bytes and
must be greater than or equal to
the startup memory size (specified with the
.B \-ms 
option).
.sp 1n
By default,
.I x
is measured in bytes. To specify
.I x
in either kilobytes or megabytes, append the
letter "k" for kilobytes or the letter "m" for
megabytes.
.br
.ne 4
.TP 15
.B \-noasyncgc
Turns off asynchronous garbage collection. When
activated no garbage collection takes place unless it
is explicitly called or the program runs out of memory.
Normally garbage collection runs as an asynchronous
thread in parallel with other threads.
.TP 15
.B  \-noclassgc
Turns off garbage collection of Java classes. By default, the Java
interpreter
reclaims space for unused Java classes during garbage collection.
.TP 15
.B \-noverify
Turns verification off.
.TP 15 
.BI \-oss x
Each Java thread has two stacks: one for Java code and
one for C code. The 
.B \-oss 
option sets the maximum stack
size that can be used by Java code in a thread to
.I x.
Every thread that is spawned during the execution of
the program passed to
.B java
has
.I x
as its Java stack
size. The default units for
.I x
are bytes
and
.I x
must be >
1000 bytes.
.sp 1n
To modify the meaning of
.IR x ,
append either the
letter "k" for kilobytes or the letter "m" for
megabytes. The default stack size is 400 kilobytes
(\f3\-oss400k\f1).
.TP 15
.B  \-prof
Starts 
Java runtime
with 
.BR java (1)
profiling enabled.
By default, this puts profile results in the
file 
.BR ./java.prof .
This option only works with
.BR  java_g .
.TP 15 
.BI \-prof file
Starts
Java runtime
with 
.BR java (1)
profiling enabled. This
form of the option allows the user to specify a
different output file for the profile information.
For example, the option 
.B  \-prof:myprog.prof 
enables profiling and puts the profile results in the file 
.B myprog.prof 
rather than in the default file 
.BR ./java.prof .
.TP 15 
.BI \-ss x
Each Java thread has two stacks: one for Java code and
one for C code. The 
.B \-ss 
option sets the maximum stack
size that can be used by C code in a thread to
.I x.
Every
thread that is spawned during the execution of the
program passed to
.B java
has
.I x
as its C stack size. The
default units for
.I x
are bytes
and
.I x
must be > 1000 bytes.
.sp 1n
To modify the meaning of
.IR x ,
append either the
letter "k" for kilobytes or the letter "m" for
megabytes. The default stack size is 128 kilobytes
(\f3\-ss128k\f1).
.TP 15
.B \-t
Prints a trace of the instructions executed (\f3java_g\f1 only).
.TP 15
.BR  \-v " | " \-verbose
Causes
.B java
to print a message to 
.B stdout 
each time a
class file is loaded.
.TP 15 
.B \-verbosegc
Causes the garbage collector to print messages
whenever it frees memory.
.TP 15
.B \-verify
Runs the verifier on all code.
.br
.ne 2
.TP 15 
.B \-verifyremote
Runs the verifier on all code that is loaded into the
system via a classloader. 
The
.B \-verifyremote
option
is the default
for the interpreter.
.TP 15
.B \-version
Displays the build version information.
.SH USAGE
The
.B java
command uses the JIT compiler by default. 
Either of the following methods may be used to disable this default:
(1) set the
.SB JAVA_COMPILER
environment variable to "NONE", or 
(2) use the
.B \-D 
option as follows:
.sp 1n
.RS
\f3example% java -Djava.compiler=none \f2classname\f1
.RE
.sp 1n
.SH ENVIRONMENT VARIABLES
.TP 15 
.SB CLASSPATH
Used to provide the system with a path to user-defined
classes.  Directories are separated by colons, for
example:
.RS 20
.sp 1n
.B .:/home/avh/classes:/usr/local/java/classes
.sp 1n
.RE
.TP 15
.SB JAVA_COMPILER
Overrides the default value for the property
.B java.compiler 
uses to speed program execution.
The default value is \*(lqsunwjit\*(rq
which causes the file
.B libsunwjit.so
to be used.
A value of \*(lqNONE\*(rq turns off
compilation.
.br
.ne 4
.SH FILES
.TP 20
.B  libsunwjit.so
Library containing runtime bytecode 
optimization files.
.SH ATTRIBUTES
See
.BR attributes (5)
for descriptions of the following attributes:
.br
.ne 11
.sp 1n
.TS
box;
cbp-1 | cbp-1
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
=
Availability	SUNWjvrt
.TE
.SH SEE ALSO
.BR javac (1),
.BR javadoc (1),
.BR javah (1),
.BR javap (1),
.BR jdb (1)