title: Groovy shell returning error on show and purge commands
body: <p>I've been trying to play around with Groovy to see if it would be a good tool to add to the arsenal. I opened up the shell using <em>groovysh</em> and was going over the commands. When I got to <em>show</em> and <em>purge</em> I got back this error(entire contents of shell, formatted):</p>
  
  <p><code>Groovy Shell (1.8.5, JVM: 1.6.0_23)<br>
  Type 'help' or '\h' for help.</p>
  
  <p>groovy:000> show<br>
  ERROR java.lang.IncompatibleClassChangeError:<br>
  the number of constructors during runtime and compile time for java.lang.Exception do not match. Expected 5 but got 4<br>
          at java_lang_Runnable$run.call (Unknown Source)</p>
  
  <p>groovy:000><br></code></p>
  
  <p>All I've found so far is that this might happen with Java 7 or when trying to integrate, but I'm using Java 6 and a fresh, empty Groovy shell.</p>
  
  <p>Thanks.</p>