Java Update 4 -- "Safe" java-vm-args Arguments for Java Web Start?

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Java Update 4 -- "Safe" java-vm-args Arguments for Java Web Start?

Sun's Java documentation notes that JNLP files can request arbitrary arguments to the virtual machine using the java-vm-args argument. However, only arguments considered "safe" will be recognized. The JNLP spec doesn't list the safe arguments, since the list might change on a per-release basis.

Unfortunately I can't find a current list of safe arguments either on Apple's site or Sun's site. I am fairly sure that -Xss is no longer on the safe list, since it's not working any more, but it would be nice to have that confirmed.

Anyone have any ideas/pointers?

Mac Pro, Mac OS X (10.5.7)

Posted on Jul 5, 2009 7:05 PM

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Answer 1

b3av1s

Level 4

1,010 points

Jul 5, 2009 10:32 PM in response to Bryant Durrell

Take a look here towards the bottom of the page you will find what you need.

Message was edited by: b3av1s

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Answer 2

Jul 6, 2009 4:36 AM in response to b3av1s

I'm pretty sure that list is not accurate for the Java Web Start released in Update 4 recently. I have an app which attempts to specify heap and stack sizes using java-vm-args="-Xmx1024m -Xms1024m -Xss8m"; when I use the Java console to display memory usage, it shows that the heap is 81MB (which is the default). If I use initial-heap-size="1024m" max-heap-size="1024m" in the same JNLP file, the heap size is set properly.

Unfortunately I don't think there's any way other than -Xss to set the stack size in a JNLP file, and I need to do that too.

It's also possible that I screwed something up which caused this problem, but I reproduced it on both my Mac Pro and my Macbook Pro.

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Answer 3

b3av1s

Level 4

1,010 points

Jul 6, 2009 6:40 PM in response to Bryant Durrell

The problem is Apple releases their own version of Java which causes other issues. Apple does have a Java Preferences utility where you can switch the version to 6, 1.42 or 5 simply by dragging the preferred version to the top. This program is in Applications:Utilities. You could switch to version 6 and see if that made a difference.

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Answer 4

Jul 6, 2009 7:22 PM in response to b3av1s

Yes, yes it does. 🙂

I've tried both versions. (1.42 won't work; the app requires 1.5 or later.) Neither of them work.

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