Krakatau
Krakatau provides tools to decompile, assemble, and disassemble Java bytecode.
About Krakatau
Krakatau provides an assembler and disassembler for Java bytecode. The assembler converts human-readable assembly into class files, and the disassembler turns class files or JAR/ZIP archives into text that can be edited and reassembled. It can also examine low-level binary details. The decompiler is aimed at obfuscated code but lacks support for some Java 8+ features such as lambdas, so it works best on older code; the v2 decompiler is still in progress, so decompilation currently requires v1. Building it requires Rust and Cargo.
Pricing is not clearly stated.
Key features
- Default disassembly mode optimized for readability and editing
- Roundtrip disassembly mode for bit-for-bit identical reassembly
- Assembler supports the Java 19 bytecode specification
- Can create class files from scratch by writing bytecode manually
- Handles highly obfuscated code that breaks javap
Best for: Bytecode-level inspection and editing of Java class files.
Krakatau at a glance
- Category
- Development › Developer Tools
- Type
- Open-source project
- Pricing
- Not confirmed. Check the site
- Details verified
- Oct 23, 2026 · Official source
- Open source
- Yes · Source code
- Language
- English
- Last checked
- Oct 5, 2026 · Online when checked
- Listed
- Oct 5, 2026
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