NAME
java - Java application launcher
SYNOPSIS
jjaavvaa [ options ] class [ argument... ]jjaavvaa [ options ] -jjaarr file.jar
[ argument... ] PPAARRAAMMEETTEERRSSoptions Command-line options.
class Name of the class to be invoked. file.jar Name of the jar file to be invoked. Used only with the-jjaarr option.
argument Argument passed to the mmaaiinn function.DESCRIPTION
The jjaavvaa tool launches a Java application. It does this by starting a Java runtime environment, loading a specified class, and invoking that class's mmaaiinn method. The method must be declared ppuubblliicc and ssttaattiicc ,, it must not return any value, and it must accept a SSttrriinngg array as a parameter. The method declaration must look like the following: ppuubblliicc ssttaattiicc vvooiidd mmaaiinn((SSttrriinngg aarrggss[[]]))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 -jjaarr
option is specified, the first non-option argument is the name of a JAR
archive containing class and resource files for the application, withthe startup class indicated by the Main-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. OOPPTTIIOONNSS The launcher has a set of standard options that are supported on the current runtime environment and will be supported in future releases.In addition, the current impletmentations of the virtual machines sup-
port a set of non-standard options that are subject to change in future
releases. Standard Options-cclliieenntt Selects the Java HotSpot Client VM. For more
information see Server-Class Machine Detection at
http://java.sun.com/j2se/1.5.0/docs/guide/vm/server-
class.html-sseerrvveerr Selects the Java HotSpot Server VM. For more
information see Server-Class Machine Detection at
http://java.sun.com/j2se/1.5.0/docs/guide/vm/server-
class.html-aaggeennttlliibb::lliibbnnaammee[=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 athttp://java.sun.com/j2se/1.5.0/docs/guide/jvmti/jvmti.html
-aaggeennttppaatthh::ppaatthhnnaammee[=options]
Load a native agent library by full pathname. For more informa-
tion, see JVMTI Agent Command Line Options athttp://java.sun.com/j2se/1.5.0/docs/guide/jvmti/jvmti.html
-ccllaassssppaatthh classpath
-ccpp classpath
Specifies a list of directories, JAR archives, and ZIP archives to search for class files. Class path entries are separated bycolons (:). Specifying -ccllaassssppaatthh or -ccpp overrides any setting
of the CCLLAASSSSPPAATTHH environment variable.If -ccllaassssppaatthh and -ccpp are not used and CCLLAASSSSPPAATTHH is not set, the
user class path consists of the current directory (.).-DDproperty=value
Sets a system property value.-dd3322, -dd6644
Specified 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 oper-
ations and the -sseerrvveerr option is implicit with the use of -dd6644 ..
This is subject to change in a future release.If neither -dd3322 nor -dd6644 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.-eennaabblleeaasssseerrttiioonnss :
... |: -eeaa :
Enable assertions. Assertions are disabled by default.... |: With no arguments, eennaabblleeaasssseerrttiioonnss or -eeaa enable assertions.
With one argument ending in "...", the switch enables assertions in the specified package and any subpackages. If the argument issimply "...", the switch enables assertions in the unnamed pack-
age in the current working directory. With one argument not end-
ing 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 assertionsenabled only in ppaacckkaaggee com.wombat.fruitbat (and any subpack-
ages), the following command could be used:jjaavvaa -eeaa::ccoomm..wwoommbbaatt..ffrruuiittbbaatt...... <
> The -eennaabblleeaasssseerrttiioonnss and -eeaa switches apply to all ss loaders
and to system classes (which do not have a class loader). Thereis one exception to this rule: in their no-argument form, the
switches do not apply to system. This makes it easy to turn on asserts in all classes except for system classes. A separate switch is provided to enable asserts in all system classes; see-eennaabblleessyysstteemmaasssseerrttiioonnss below.
-ddiissaabblleeaasssseerrttiioonnss :
... |: -ddaa :
Disable assertions. This is the default.... |: /fR With no arguments, ddiissaabblleeaasssseerrttiioonnss or -ddaa disables assertions.
With one argument ending in "...", the switch disables asser-
tions in the specified package and any subpackages. If the argu-
ment is simply "...", the switch disables assertions in the unnamed package in the rent working directory. With one argumentnot ending in "...", the switch disables assertions in the spec-
ified class.To run a program with assertions enabled in package ccoomm..wwoomm-
bbaatt..ffrruuiittbbaatt but disabled in class ccoomm..wwoommbbaatt..ffrruuiittbbaatt..BBrriicckkbbaatt, the following command could be used:jjaavvaa -eeaa::ccoomm..wwoommbbaatt..ffrruuiittbbaatt...... -ddaa::ccoomm..wwoommbbaatt..ffrruuiittbbaatt..BBrriicckkbbaatt
<> The -ddiissaabblleeaasssseerrttiioonnss and -ddaa switches apply to all ssss loaders
and to system classes (which do not have a class loader). Thereis one exception to this rule: in their no-argument form, the
switches do not apply to system. This makes it easy to turn on asserts in all classes except for system classes. A separate switch is provided to enable asserts in all system classes; see-ddiissaabblleessyysstteemmaasssseerrttiioonnss below.
-eennaabblleessyysstteemmaasssseerrttiioonnss
-eessaa Enable asserts in all system classes (sets the default assertion
status for system classes to true).-ddiissaabblleessyysstteemmaasssseerrttiioonnss
-ddssaa Disables asserts in all system classes
-jjaarr Execute a program encapsulated in a JAR archive. The first
argument is the name of a JAR file instead of a startup class name. In order for this option to work, the manifest of the JARfile must contain a line of the form MMaaiinn-CCllaassss::classname.
Here, classname identifies the class having the ppuubblliicc ssttaattiiccvvooiidd mmaaiinn((SSttrriinngg[[]] aarrggss)) method that serves as your applica-
tion's starting point. See the Jar tool reference page and the Jar trail of the Java Tutorial for information about workingwith Jar files and Jar-file manifests.
When you use this option, the JAR file is the source of all user classes, and other user class path settings are ignored.Note that JAR files that can be run with the "java -jar" option
can have their execute permissions set so they can be run with-
out using "java -jar". Refer to Java Archive (JAR) Files.
-jjaavvaaaaggeenntt::jjaarrppaatthh[=options]
Load a Java programming language agent, see java.lang.instru-
ment.-vveerrbboossee
-vveerrbboossee::class
Displays information about each class loaded.-vveerrbboossee::ggcc
Reports on each garbage collection event.-vveerrbboossee::jjnnii
Reports information about use of native methods and other Java Native Interface activity.-vveerrssiioonn
Displays version information and exit.-sshhoowwvveerrssiioonn
Displays version information and continues.-??
-hheellpp Displays usage information and exit.
-XX Displays information about non-standard options and exit.
NonStandard Options-XXiinntt Operates in interpreted-only mode. Compilation to
native code is disabled, and all bytecodes are exe-
cuted by the interpreter. The performance benefits offered by the Java HotSpot VMs' adaptive compiler will not be present in this mode.-XXbbaattcchh Disable background compilation. Normally the VM
will compile the method as a background task, run-
ning the method in interpreter mode until the back-
ground compilation is finished. The -Xbatch flag
disables background compilation so that compilation of all methods proceeds as a foreground task until completed.-XXddeebbuugg Start with support for JVMDI enabled. JVMDI has
been deprecated and is not used for debugging in J2SE 5.0, so this option isn't needed for debugging in J2SE 5.0.-XXbboooottccllaassssppaatthh::bootclasspath
Specify a colon-separated list of directories, JAR
archives, and ZIP archives to search for boot class files. These are used in place of the boot classfiles included in the Java 2 SDK. Note: Applica-
tions that use this option for the purpose of over-
riding a class in rt.jar should not be deployed asdoing so would contravene the Java 2 Runtime Envi-
ronment binary code license.-XXbboooottccllaassssppaatthh//aa::path
Specifies a colon-separated path of directories,
JAR archives, and ZIP archives to append to the default bootstrap class path.-XXbboooottccllaassssppaatthh//pp::path
Specifies a colon-separated path of directories,
JAR archives, and ZIP archives to prepend in frontof the default bootstrap class path. Note: Appli-
cations that use this option for the purpose of overriding a class in rrtt..jjaarr should not be deployed, as doing so would contravene the Java 2 Runtime Environment binary code license.-XXcchheecckk::jjnnii Perform additional checks for Java Native Interface
(JNI) functions. Specifically, the Java Virtual Machine validates the parameters passed to the JNI function as well as the runtime environment data before processing the JNI request. Any invalid data encountered indicates a problem in the native code, and the Java Virtual Machine will terminate with a fatal error in such cases. Expect a performance degradation when this option is used.-XXffuuttuurree Performs strict class-file format checks. For pur-
poses of backwards compatibility, the default for-
mat checks performed by the Java 2 SDK's virtual machine are no stricter than the checks performedby 1.1.x versions of the JDK software. The -XXffuu-
ttuurree flag turns on stricter class-file format
checks that enforce closer conformance to theclass-file format specification. Developers are
encouraged to use this flag when developing new code because the stricter checks will become the default in future releases of the Java application launcher.-XXnnooccllaassssggcc Disables class garbage collection
-XXiinnccggcc Enable the incremental garbage collector. The
incremental garbage collector, which is off bydefault, will reduce the occasional garbage-collec-
tion pauses during program execution. The incremen-
tal garbage collector will at times execute concur-
rently with the program and during such times willreduce the processor capacity available to the pro-
gram.-XXllooggggcc:: file Report on each garbage collection event, as with
-vveerrbboossee::ggcc, but log this data to file. In addi-
tion to the information -vveerrbboossee::ggcc gives, each
reported event will be preceeded by the time (inseconds) since the first garbage-collection event.
Always use a local file system for storage of this file to avoid stalling the JVM due to network latency. The file may be truncated in the case of a full file system and logging will continue on thetruncated file. This option overrides -vveerrbboossee::ggcc
if both are given on the command line.-XXmmssn Specifies the initial size of the memory allocation
pool. This value must be a multiple of 1024 greater than 1 MB. Append the letter kk or KK to indicate kilobytes, the letter mm or MM to indicate megabytes, the letter gg or GG to indicate gigabytes, or the letter tt or TT to indicate terabytes. The default value is 2MB. Examples:-Xms6291456
-Xms6144k
-Xms6m
-XXmmxxn Specifies the maximum size, in bytes, of the memory
allocation pool. This value must be a multiple of 1024 greater than 2 MB. Append the letter kk or KKto indicate kilobytes, the letter mm or MM to indi-
cate megabytes, the letter gg or GG to indicate giga-
bytes, or the letter tt or TT to indicate terabytes. The default value is 64MB. Examples:-Xmx83886080
-Xmx81920k
-Xmx80m
On Mac OS X platforms, the upper limit for thisvalue when running in 32-bit mode (-dd3322) is approx-
imately 2100m minus overhead amounts, and approxi-
mately 127t minus overhead amounts when running in64-bit mode (-dd6644). On Solaris 7 and Solaris 8
SPARC platforms, the upper limit for this value is approximately 4000m minus overhead amounts. On Solaris 2.6 and x86 platforms, the upper limit is approximately 2000m minus overhead amounts. On Linux platforms, the upper limit is approximately 2000m minus overhead amounts.-XXpprrooff Profiles the running program, and sends profiling
data to standard output. This option is provided as a utility that is useful in program development and is not intended to be be used in production systems.-XXrruunnhhpprrooff[:help][:suboption==value,...]
Enables cpu, heap, or monitor profiling. Thisoption is typically followed by a list of comma-
separated suboption=value pairs. Run the commandjjaavvaa -XXrruunnhhpprrooff::hheellpp to obtain a list of suboptions
and their default values.-XXrrss Reduce usage of operating-system signals by Java
virtual machine (JVM). In a previous release, the Shutdown Hooks facility was added to allow orderly shutdown of a Java application. The intent was to allow user cleanup code (such as closing database connections) to run at shutdown, even if the JVM terminates abruptly. Sun's JVM catches signals to implement shutdown hooks for abnormal JVM termination. The JVM uses SIGHUP, SIGINT, and SIGTERM to initiate the running of shutdown hooks. The JVM uses a similar mechanism to implement thepre-1.2 feature of dumping thread stacks for debug-
ging purposes. Sun's JVM uses SIGQUIT to perform thread dumps. Applications that embed the JVM frequently need to trap signals like SIGINT or SIGTERM, which can lead to interference with the JVM's own signal handlers.The -XXrrss command line option is available to
address this issue. When -XXrrss is used on Sun's
JVM, the signal masks for SIGINT, SIGTERM, SIGHUP, and SIGQUIT are not changed by the JVM, and signal handlers for these signals are not installed.There are two consequences of specifying -XXrrss:
+o SIGQUIT thread dumps are not available. +o User code is responsible for causing shutdownhooks to run, for example by calling Sys-
tem.exit() when the JVM is to be terminated.-XXssssn Set thread stack size.
-XXXX::++UUsseeAAllttSSiiggss The VM uses SIGUSR1 and SIGUSR2 by default, which
can sometimes conflict with applications that sig-
nal-chain SIGUSR1 and SIGUSR2. The -XXXX::++UUsseeAAllttSSiiggss
option will cause the VM to use signals other than SIGUSR1 and SIGUSR2 as the default.SEE ALSO
jjaavvaacc(1), jjddbb(1), jjaavvaahh(1), jjaarr(1), See (or search jjaavvaa..ssuunn..ccoomm) for the following: The Java Extensions Framework @http://java.sun.com/j2se/1.5.0/docs/guide/extensions/index.html
SSeeccuurriittyy FFeeaattuurreess @@http://java.sun.com/j2se/1.5.0/docs/guide/security/index.html
23 June 2004 java(1)