Java Tools Tutorials - Herong's Tutorial Notes - Version 5.32, by Dr. Herong Yang
'java' - Java Launching Command and Options
This section describes the Java launching tool 'java' and its commonly used command options.
"java": A command line tool that launches Java applications. It starts a Java virtual machine, loads the specified class, and invokes that class's main method. "java" has the following syntax:
java [options] class [arguments]
where "options" is a list of options; "class" is the full name of a Java class to be launched; "arguments" is a list of arguments to be passed to the main method of the class to be launched.
Another way of launching a Java class is to use the "-jar" option:
java [options] -jar file [arguments]
where "file" is a JAR file, which should contain a "Main-Class" attribute in the manifest file. The "Main-Class" attribute defines the Java class to be launched.
Commonly used options are:
If you run the "java" command without any options, you will get the quick usage information as shown below:
C:\herong>\progra~1\java\jdk1.8.0\bin\java Usage: java [-options] class [args...] (to execute a class) or java [-options] -jar jarfile [args...] (to execute a jar file) where options include: -d32 use a 32-bit data model if available -d64 use a 64-bit data model if available -client to select the "client" VM -server to select the "server" VM The default VM is client. -cp <class search path of directories and zip/jar files> -classpath <class search path of directories and zip/jar files> A ; separated list of directories, JAR archives, and ZIP archives to search for class files. -D<name>=<value> set a system property -verbose:[class|gc|jni] enable verbose output -version print product version and exit -version:<value> require the specified version to run -showversion print product version and continue -jre-restrict-search | -no-jre-restrict-search include/exclude user private JREs in the version search -? -help print this help message -X print help on non-standard options -ea[:<packagename>...|:<classname>] -enableassertions[:<packagename>...|:<classname>] enable assertions with specified granularity -da[:<packagename>...|:<classname>] -disableassertions[:<packagename>...|:<classname>] disable assertions with specified granularity -esa | -enablesystemassertions enable system assertions -dsa | -disablesystemassertions disable system assertions -agentlib:<libname>[=<options>] load native agent library <libname>, e.g. -agentlib:hprof see also, -agentlib:jdwp=help and -agentlib:hprof=help -agentpath:<pathname>[=<options>] load native agent library by full pathname -javaagent:<jarpath>[=<options>] load Java programming language agent, see java.lang.instrument -splash:<imagepath> show splash screen with specified image
Last update: 2015.
Table of Contents
'javac' - The Java Program Compiler
►'java' - The Java Program Launcher
►'java' - Java Launching Command and Options
Launching Hello.java - My First Java Program
Option "-classpath" - Specifying Class Path
Option '-jar' - Specifying Executable JAR Files
Option '-X' - Specifying Non-Standard Options
'javaw' - Launching Java Programs without Console
'jconsole' - Java Monitoring and Management Console
'jstat' - JVM Statistics Monitoring Tool
jvisualvm (Java VisualVM) - JVM Visual Tool
'javap' - The Java Class File Disassembler
'keytool' - Public Key Certificate Tool