title: How is the Eclipse JDK setting affecting the system's JDK setting
body: <p>I was trying to compile a Grails application referencing third party JARs on Mac OSX. Although my system's JRE and JDK is set to Java 1.6 I always got a <code>Compilation error: java.lang.UnsupportedClassVersionError: Bad version number in .class file</code>
  when accessing classes in the JAR. Also when testing an existing Grails app the default stats of the app where showing that it's running with Java 1.6. So I really didn't have more ideas than to try to change the Java settings in Eclipse - I thought that's stupid as I'm not using Eclipse for the devlopment of this application - but voila - now the compilation of my app on the command line works just fine!</p>
  
  <p>Can anyone explain me what Eclipse is doing here behind the scenes?
  I've had set the JAVA_HOME manually before with no effect.</p>