Bytecode Viewer
Information on Bytcode Viewer.
Bytecode Viewer is a Java Bytecode Viewer, GUI Procyon Java Decompiler, GUI CFR Java Decompiler, GUI FernFlower Java
Decompiler, GUI Jar-Jar, Hex Viewer, Code Searcher, Debugger and more.
It's written completely in Java, and it's open sourced. It's currently being maintained and developed by Konloch.

There is also a plugin system that will allow you to interact with the loaded classfiles, for example you can write a String 
deobfuscator,a malicious code searcher, or something else you can think of.
You can either use one of the pre-written plugins, or write your own. It supports groovy, python and ruby scripting.
Once a plugin is activated, it will send a ClassNode ArrayList of every single class loaded in the file system to the execute function,
this allows the user to handle it completely using ASM.

Code from various projects has been used, including but not limited to:
    J-RET by WaterWolf
    JHexPane by Sam Koivu
    JSynaxPane by Ayman Al
    Commons IO by Apache
    ASM by OW2
    FernFlower by Stiver
    Procyon by Mstrobel
    CFR by Lee Benfield

    APK/DEX Support - Using Dex2Jar and Jar2Dex it's able to load and save APKs with ease!
    Java Decompiler - It utilizes FernFlower, Procyon and CFR for decompilation.
    Bytecode Decompiler - A modified version of CFIDE's.
    Hex Viewer - Powered by JHexPane.
    Each Decompiler/Viewer is toggleable, you can also select what will display on each pane.
    Fully Featured Search System - Search through strings, functions, variables and more!
    A Plugin System With Built In Plugins - (Show All Strings, Malicious Code Scanner, String Decrypters, etc)
    Fully Featured Scripting System That Supports Groovy, Python And Ruby.
    EZ-Inject - Graphically insert hooks and debugging code, invoke main and start the program.
    Recent Files & Recent Plugins.
    And more! Give it a try for yourself!

Video of it in action (Beta 1.5.2):

Source Code:
Java Docs:
License (Copyleft):
Soft82: Mac Section, Windows Section

About The Bytecode Club

We're a community focused on Reverse Engineering, we try to target Java/Android but we also include other langauges/platforms. We pride ourselves in supporting and free and open sourced applications.