Today, I finished my new extension named 'ClearAll'. This extension provides a button in the jdeveloper toolbar to clean up the compiler log, message log and running server log in one click.
You can get it from the update centre by going to jdeveloper and clicking on check for updates.
Make sure to check the thrid party developer extensions.
Click next and select ClearAll from the list of available extensions.
Just do a next and restart jdeveloper.
After a restart a eraser icon button will appear in the jdeveloper toolbar. You can just click on it any time to clear all the log windows like compiler log pane, message log pane and running wls log pain.