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

问题

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.formatasdefault=true when starting a JVM instance.

I would like to set this flag permanently so that I don't have to specify it in command line arguments each time when I start a JVM instance. Is there a file or any other possibility to change the default settings for JVM? Something like the Eclipse.ini file but for the JVM itself?

回答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

来源：https://stackoverflow.com/questions/12577437/how-to-set-a-java-system-property-so-that-it-is-effective-whenever-i-start-jvm-w