http://www.intellij.net/tracker/idea/viewSCR?publicId=29310 From omnicore's web site: http://www.omnicore.com/htmls/newdebugger.html JDK and library debugging CodeGuide displays variable information for classes even if the corresponding sources have not been compiled with debugging information. This enables out-of-the-box debugging in the JDK sources. I want to have that in Idea, please! Would be so nice to see argument values in JDK sources. I wonder how they did it? Possibly guessing which index a local variable has depending on the declaration order?