Java System Environment Variable

Question

Does Java have a default System Environment Variable that will always be read/appended when we set it? CATALINA_OTPS/JAVA_OPTS etc seems only for T

Answer 1

There is a special environment variable called _JAVA_OPTIONS, its value will be picked up by the JVM (java.exe).

In Windows:

set _JAVA_OPTIONS=-Xms64m -Xmx128m -Dawt.useSystemAAFontSettings=lcd

In Linux:

export _JAVA_OPTIONS='-Xms64m -Xmx128m -Dawt.useSystemAAFontSettings=lcd'

For Java Web Start it's JAVAWS_VM_ARGS. For javaw.exe (Applet), it's _JPI_VM_OPTIONS.

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edit 20201213

_JAVA_OPTIONS environment variable was ok but was not documented or supported. Since it is not standardized, other vendors have their own names e.g. IBM_JAVA_OPTIONS. Leading underscore names are private by convention so it's not a good idea to standardize the usage of _JAVA_OPTIONS. That's why JAVA_TOOL_OPTIONS should be the preferred choice.

ref : https://docs.oracle.com/javase/8/docs/platform/jvmti/jvmti.html#tooloptions

Answer 2

Java has a standard OS system environment variable that is always set when the JVM is launched:

• os.name
• os.arch
• os.version

All accessible via 'System.getProperty(propertyName)`

If you need anything more than this you could always use the Management API.