Desc: 
  this issue can be observed ONLY if 7u2 b08/b09 is used simultaneously 
     - for running harness ( javatest ) which start http server
        where jnlp app is deployed
     - for executing jnlp application ( client part )

Test running under harness requests some permissions ( access to clipboard, etc ).

This issue looks like security warning window ( "Access to clipboard .." or other access request ) for jnlp application responds slowly, fails to render and finally jnlp application hangs ( javaw process still consumes CPU in this moment )
It's hard to click on allow button, warning window doesn't respond.

See details in comments.