How to run a jnlp file with Java?

I have a jnlp file, normally i will execute with console (Linux) and works perfect.

javaws launch.jnlp 

But now I have to run from Java code, i tried this...

Process p = Runtime.getRuntime().exec(new String[]{"path/to/.jnlp"});

p.waitFor();

not working. as it should run ???

I hope you can help me, sorry for my English.