java - the Java application launcher (original) (raw)

The java tool launches a Java application. It does this by starting a Java runtime environment, loading a specified class, and invoking that class's main method.

The method must be declared public and static, it must not return any value, and it must accept a String array as a parameter. The method declaration must look like the following:

public static void main(String args[])

By default, the first non-option argument is the name of the class to be invoked. A fully-qualified class name should be used. If the -jar option is specified, the first non-option argument is the name of a JAR archive containing class and resource files for the application, with the startup class indicated by theMain-Class manifest header.

The Java runtime searches for the startup class, and other classes used, in three sets of locations: the bootstrap class path, the installed extensions, and the user class path.

Non-option arguments after the class name or JAR file name are passed to the main function.

-client

Select the Java HotSpot Client VM.

For more information, see Server-Class Machine Detection

-server

Select the Java HotSpot Server VM.

For more information, see Server-Class Machine Detection

-agentlib:libname[=options]

Load native agent library libname, e.g.

-agentlib:hprof

-agentlib:jdwp=help

-agentlib:hprof=help

For more information, see JVMTI Agent Command Line Options.

-agentpath:pathname[=options]

Load a native agent library by full pathname. For more information, see JVMTI Agent Command Line Options.

-classpath classpath

-cp classpath

Specify a list of directories, JAR archives, and ZIP archives to search for class files. Class path entries are separated by colons (:). Specifying-classpath or -cp overrides any setting of theCLASSPATH environment variable.

If -classpath and -cp are not used andCLASSPATH is not set, the user class path consists of the current directory (.).

For more information on class paths, see Setting the Class Path.

-Dproperty=value

Set a system property value.

-d32

-d64

Specifies whether the program is to be run in a 32-bit or 64-bit environment if available.

Currently only the Java HotSpot Server VM supports 64-bit operation, and the "-server" option is implicit with the use of -d64. This is subject to change in a future release.

If neither -d32 nor -d64 is specified, the default is to run in a 32-bit environment, except for 64-bit only systems. This is subject to change in a future release.

-enableassertions[:"..." | : ]

-ea[:"..." | : ]

Enable assertions. Assertions are disabled by default.

With no arguments, enableassertions or -ea enables assertions. With one argument ending in "...", the switch enables assertions in the specified package and any subpackages. If the argument is simply"...", the switch enables assertions in the unnamed package in the current working directory. With one argument not ending in "...", the switch enables assertions in the specified class.

If a single command line contains multiple instances of these switches, they are processed in order before loading any classes. So, for example, to run a program with assertions enabled only in package com.wombat.fruitbat (and any subpackages), the following command could be used:

java -ea:com.wombat.fruitbat...