
Apple recently released Java 6 SE through a Java update. With the release of Java 6 Mac users can now enjoy better OS X integration besides the many other improvements in Java 6.
Using Java 6 as the default JVM has implications with a standard jEdit installation on Mac. But the solution is simple…
Being a jEdit user I was eager to try out the new JVM version to see if there were any general improvements.
Since Mac users has gone long without proper OS integration, one jEdit developer (Kris Kopicki) decided to fix this with a Mac OS X plugin that included many small improvements.
With the new update Apple has completely removed the cocoa API (packages in com.apple.cocoa). The result: jEdit will fail to start with Java 6 SE.
jEdit will simply "bounce" once and then quit. This is caused by a fatal exception during startup.
The fix is simple: Remove the Mac OS X plugin.
With the improved cocoa/mac support many of the features in the plugin are unncessesary. Key-mappings are improved to use the CMD-buttons in all textareas and the menubar is now moved to the actual Mac menubar.
How to remove the plugin:
- Right click/CTRL+click the jEdit application icon
- Choose "Show Package Contents"
- Go to the Contents/Java/jars folder
- Delete the MacOS.jar file (you may need to authenticate to do this)

Launching jEdit with Java 6 SE should now be possible. Alternatively to setting Java 6 SE as your standard JVM you can set the Contents/Info.plist file property: "Root/Java/JVMVersion" to "1.6+" instead of "1.5+". Either way should work.