title: Recurring Exception without a stack trace - how to reset?
body: <p>In my application log (using log4j), I see a NullPointerException, but without the stack trace. I know that as an optimization, when an exception occurs many times - the jvm stops producing the stack trace. The problem is the exception occurred some time ago, and all my logs are filled with the exception without the stack trace. Is there a way to "reset" this mechanism, so the next thrown exception will be printed with the full stack trace? I don't want to restart the application, as it is hard to reproduce this bug, and restarting may cause to "go away"...</p>
  
  <p>Thanks!</p>