Re: Problem with jdk-1.6 (javaws)

[Ian Darwin]

 -Xmx1024m
  
That's 1 GB.
data(kbytes)         524288
  
That's 512MB.
You've told Java it can grab about 2x what you've told the OS to let it 
have.

Try -Xmx350m (since there is also the JVM and some overhead), or, 
increase your datasize with ulimit.