How to set a java system property so that it is effective whenever I start JVM without adding it to the command line arguments

Question

There was a change in Java 1.7 in the way the default Locale is get from the OS. There are methods of restoring the old behaviour e.g. by setting the flag -Dsun.locale.forma

Answer 1

You can set set environment variable JAVA_TOOL_OPTIONS in your OS. All Java tools (java, javac, ..) will pick this variable up and use it. So you could e.g. use

SET JAVA_TOOL_OPTIONS=-Dsun.locale.formatasdefault=true

I use this to force a specific locale for each JVM.

But this only works if your application is started through the Java tools. If it is e.g. started from a C program that calls the jvm DLL this won't be used.

Edit: I just tested it, and it seems JAVA_TOOLS_OPTIONS is also picked up when the DLLs are started (verified with a Swing application that uses WinRun4J as a launcher)

See: http://docs.oracle.com/javase/7/docs/webnotes/tsg/TSG-VM/html/envvars.html