Jad is the fastest java decompiler, available open source.. However it doesn’t come with a GUI. It is a command line tool. There are also GUI tools which internally use jad, and then decorate the code and show it in a graphical window.
Instead of going for a GUI tool, it is easier to write a dos-batch file, which will decompile the java class file, and opens them on your favorite text editor, say notepad/textpad.
Here is the script
===jadOpen.bat===
@echo off
jad -o -d%TEMP% %1
"C:\Program Files\TextPad 4\Textpad.exe" %TEMP%.\%~n1.jad
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Now associate class files, to open with this bat file by default, using windows program association. So now double clicking a class file will open in textpad with source code.
