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Setting java properties

Ed Zeval

Joined: Jun 19, 2008
Posts: 21

I was wondering how to set some java properties. I don't want to pass in the key/value pairs in the command line (as "-Dkey=value). Is there a way to set them in the code?

Ernest Friedman-Hill
author and iconoclast

Joined: Jul 08, 2003
Posts: 24183

Yes; the setProperty() method in the java.lang.System class can set these. Be careful because some properties take effect during JVM startup, and using setProperty() for these will not have the intended effect.

[Jess in Action][AskingGoodQuestions]
Ed Zeval

Joined: Jun 19, 2008
Posts: 21
Cool, thanks. That worked.

Now... I saw that the System.set/getProperty() methods may throw a SecurityException if I'm running a SecurityManager and I don't have permissions.

What is a SecurityManager and how do I get the necessary permissions in case I don't have them?

Norm Radder
Ranch Hand

Joined: Aug 10, 2005
Posts: 685
I think you can use policytool that comes with the jre(?)/jdk install to give your program permissions. The permissions would have to be set on every computer that you run your program on.
You'll have to read a tutorial to understand how to use policytool. In some cases I've have to manually edit the .java.policy file to get the correct paths to give my programs permissions. There has been a lot of try this, try that until I've been able to give my programs permissions.
Perhaps you won't have to do this.
Consider Paul's rocket mass heater.
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