Generally speaking, to be able to watch the variables while stepping through JDK source code, you need the class files to be compiled with debug information i.e. compile using
So your best bet is to either find an already compiled version with debug information (I couldn’t find anything for JDK 7) or you can try compiling the source for yourself.
According to this post (please note that I haven’t tried it) you don’t need to compile all sources, only the ones you need. Putting your newly compiled classes in the
endorsed directory, the new classes would be used instead the ones in the original
I believe that should get you started.
Update: Actually I have just tried this process and it is not hard at all. Tested on Windows, JDK 1.7.0_11. All the commands are invoked from command line:
- Create your working folder. I chose
- Inside your working folder create the source folder i.e.
jdk7_srcand output folder
- From your
JDK_HOMEfolder get the
src.zipfile and unzip it inside
- Select what you will compile and delete the rest. For all of them you might need additional steps. I have chosen the folders:
- From your
JDK_HOME\jre\libget the file
rt.jarand put in the work folder (this is only for convenience to not specify too large file names in the command line).
- Execute the command:
dir /B /S /X jdk7_src\*.java > filelist.txtto create a file named
filelist.txtwith the list of all java files that will be compiled. This will be given as input to
javacusing the command:
javac -J-Xms16m -J-Xmx1024m -sourcepath d:\jdk7_src -cp d:\rt.jar -d d:\jdk_debug -g @filelist.txt >> log.txt 2>&1This will compile all the files in the
jdk_debugfolder and will generate a
log.txtfile in your working folder. Check the log contents. You should get a bunch of warnings but no error.
- Go inside the
jdk_debugfolder and run the command:
jar cf0 rt_debug.jar *. This will generate your new runtime library with degug information.
- Copy that new jar to the folder
JDK_HOME\jre\lib\endorsed. If the
endorsedfolder does not exist, create it.
Debug your program in Eclipse. Note how the variables are named normally (no more arg0, arg1 etc). Happy debugging 🙂