Non-Standard Options of the Classic VM

The Java 2 Classic VM is included only in the Java 2 SDK. It is not included in the Java 2 Runtime Environment.

-Xbootclasspath:bootclasspath

Specify a semicolon-separated list of directories, JAR archives, and ZIP archives to search for boot class files. These are used in place of the boot class files included in the Java 2 SDK. Note: Applications that use this option for the purpose of overriding a class in rt.jar should not be deployed as doing so would contravene the Java 2 Runtime Environment binary code license.

-Xbootclasspath/a:path

Specify a semicolon-separated path of directires, JAR archives, and ZIP archives to append to the default bootstrap class path.

-Xbootclasspath/p:path

Specify a semicolon-separated path of directires, JAR archives, and ZIP archives to prepend in front of the default bootstrap class path. Note: Applications that use this option for the purpose of overriding a class in rt.jar should not be deployed as doing so would contravene the Java 2 Runtime Environment binary code license.

-Xdebug

Start with the debugger enabled. The Java interpereter prints out a password for jdb's use. Refer to jdb description for more details and an example.

-Xnoclassgc

Disable class garbage collection

-Xmsn

Specify the initial size of the memory allocation pool. This value must greather than 1000. To multiply the value by 1000, append the letter k. To multiply the value by 1 million, append the letter m. The default value is 1m

-Xmxn

Specify the maximum size of the memory allocation pool. This value must greather than 1000. To multiply the value by 1000, append the letter k. To multiply the value by 1 million, append the letter m. The default value is 64m.

-Xrunhprof[:help][:<suboption>=<value>,...]

Enables cpu, heap, or monitor profiling. This option is typically followed by a list of comma-separated "<suboption>=<value>" pairs. Run the command java -Xrunhprof:help to obtain a list of suboptions and their default values.

-Xrs

Reduce the use of operating system signals.

-Xcheck:jni

Perform additional checks for Java Native Interface functions.

-Xcheck:nabounds

Perform additional checks for Java Native Interface array bounds.

-Xfuture

Perform strict class-file format checks. For purposes of backwards compatibility, the default format checks performed by the Java 2 SDK's virtual machine are no stricter than the checks performed by 1.1.x versions of the JDK software. The -Xfuture flag turns on stricter class-file format checks that enforce closer conformance to the class-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.

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