bytecode-viewer README

The project's README from github.com/Konloch/bytecode-viewer. As one markdown file: README.md.

Bytecode Viewer

Bytecode Viewer - a lightweight user-friendly Java/Android Bytecode Viewer, Decompiler & More.

New Features

Key Features

Command Line Input

	-help                         Displays the help menu
	-clean                        Deletes the BCV directory
	-english                      Forces English language translations
	-list                         Displays the available decompilers
	-decompiler <decompiler>      Selects the decompiler, procyon by default
	-i <input file>               Selects the input file (Jar, Class, APK, ZIP, DEX all work automatically)
	-o <output file>              Selects the output file (Java or Java-Bytecode)
	-t <target classname>         Must either be the fully qualified classname or "all" to decompile all as zip
	-nowait                       Doesn't wait for the user to read the CLI messages

What is Bytecode Viewer?

Bytecode Viewer (BCV) is an Advanced Lightweight Java/Android Reverse Engineering Suite. Powered by several open source tools BCV is designed to aid in the reversing process.

BCV comes with 6 decompilers, 3 disassemblers, 2 assemblers, 2 APK converters, advanced searching, debugging & more.

It's written completely in Java, and it's open sourced. It's currently being maintained and developed by Konloch.

Is there a demo?

BCV Demo

Please note this demo is from a very old version

How do I install BCV?

Download the latest version from https://github.com/konloch/bytecode-viewer/releases and run the Bytecode-Viewer-2.10.x.jar. You may need to execute it via command line java -jar Bytecode-Viewer-2.10.x.jar (replace the X with the current minor version)

How can I use BCV?

How do the plugins work?

There is also a plugin system that will allow you to interact with the loaded classfiles. You could for example write a String deobfuscator, a malicious code searcher, or anything else you can think of.

You can either use one of the pre-written plugins, or write your own. The plugin system supports java and javascript scripting.

Once a plugin is activated, it will execute the plugin with a ClassNode ArrayList of every single class loaded in BCV, this allows the user to handle it completely using ASM.

Instructions to compile

Just clone this repo and run mvn package. It's that simple!

Working on the source

Open the Maven project (e.g. in IntelliJ, open the pom.xml as a project file).

UI Is Lagging

Change the theme to your systems. Go into View->Visual Settings->Window Theme and select System Theme.

Java Heap Space Issues (java.lang.OutOfMemoryError)

Start BCV with more RAM, e.g. java -Xmx3G -jar BCV.jar

File Permission Issues (java.io.FileNotFoundException)

Right click on the jar file, go to Properties, and select Unblock under Security at the bottom of the General tab.

APK File Permission Issues (java.io.FileNotFoundException)

Run BCV as administrator.

Are you a Java Reverse Engineer? Do you want to learn?

Join The Bytecode Club Today! - https://the.bytecode.club

bytecode-viewer (Konloch/bytecode-viewer)

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15.7K ·GitHub
Bytecode-viewer
What is this?Bytecode Viewer (BCV) is a lightweight Java/Android reverse engineering suite: drag in a Jar or APK and it decompiles, disassembles, searches and debugs it, powered by several open source tools.
Is this a desktop app or something I use in the browser?It's a desktop application written entirely in Java with a full GUI (dark mode by default), not a web service — you run it locally. It also accepts command line input.
How do I get it running?Download the latest Bytecode-Viewer jar and run it (via java -jar if double-clicking doesn't work); you need a Java 8+ runtime. To build from source, clone the repo and run mvn package.
Any gotchas with big files or on Windows?Large inputs can exhaust the heap — relaunch with more RAM, e.g. java -Xmx3G -jar BCV.jar. On Windows you may need to Unblock the jar in its properties, and APK permission errors require running as administrator.
Which languages is the interface translated into?Over 30, including Arabic, German, Japanese, Mandarin, Russian and Spanish. Dark mode is on by default with multiple themes, and if the UI lags you can switch to your system theme in the visual settings.
Is it useful for malware analysis?Yes — it ships a malicious code scanning API, and the plugin system is designed for exactly this kind of work, like writing malicious code searchers or string deobfuscators that run over every loaded class.
What's new in recent releases?Recent versions added jump-to-declaration, draggable tabs, a Plugin Writer for creating plugins inside BCV, a Javap disassembler, XAPK support, JDK 13+ file support and a fix for CVE-2022-21675 — make sure you're on v2.11.X.
What are similar projects?jadx, radare2, dex2jar, ASC, Apktool, dnSpy, jd-gui, Detect-It-Easy
Which topics is it in?bytecode, malware, debugger, decompiler, apk, static-analysis, compiler, editor, reverse-engineering, java, hacktoberfest, android
Creator
Konloch
Size
633.5 MB
Stars
15.7K
Updated
CommitJul 17Releasev2.13.2Jan 01
Age
12y
Commits · 90 Days