Determined to crack the code, Jack fired up his trusty decompiler, a powerful tool that could translate the compiled Java bytecode back into readable source code. He loaded the ShadowTrader.class file into the decompiler and clicked the "Decompile" button.
JD-GUI is perhaps the most classic choice. It’s a standalone graphical utility that lets you drag and drop .class or .jar files to view the source code instantly. Fast, easy to use, supports "Go to Declaration." Cons: Hasn't been updated as frequently as newer engines. decompile class file