Although the command line is the traditional way to specify
command-line options, you can pass options to the JVM in other ways.
Use only single or double quotation marks for command-line
options when explicitly directed to do so for the option in question.
Single and double quotation marks have different meanings on different
platforms, operating systems, and shells. Do not use '-X<option>' or "-X<option>".
Instead, you must use -X<option>. For example,
do not use '-Xmx500m' and "-Xmx500m".
Write this option as -Xmx500m.
These precedence rules (in descending order) apply to specifying
options:
- Command line.
For example, java -X<option> MyClass
- A file containing a list of options, specified using the –Xoptionsfile option
on the command line. For example, java -Xoptionsfile=myoptionfile.txt
MyClass
In the options file, specify each option on a
new line; you can use the '\' character as a continuation character
if you want a single option to span multiple lines. Use the '#' character
to define comment lines. You cannot specify
-classpath in an
options file. Here is an example of an options file:
#My options file
-X<option1>
-X<option2>=\
<value1>,\
<value2>
-D<sysprop1>=<value1>
- IBM_JAVA_OPTIONS environment variable. You can set command-line
options using this environment variable. The options that you
specify with this environment variable are added to the command line
when a JVM starts in that environment.
For example, set
IBM_JAVA_OPTIONS=-X<option1> -X<option2>=<value1>