I've been struggling for a while to make the JS debugger working again after migrating from Alfresco 5.x Alfresco 6.2. The Alfresco instance is running on a CentOS 7 server.
The error message is a "No X11 DISPLAY variable was set, but this program performed an operation which requires it."
I tried to force the console working headless with the JAVA_OPTS -Djava.awt.headless=true but it resulted in a Headless Exception with a "cannot resolve reference to bean 'rhinoScriptDebugger'" message.
If I put headless back to false, set and launch X as follows :