Java Bytecode Manipulation

Open-source Java projects categorized as Bytecode Manipulation

Top 12 Java Bytecode Manipulation Projects

Bytecode Manipulation
  1. bytecode-viewer

    A Java 8+ Jar & Android APK Reverse Engineering Suite (Decompiler, Editor, Debugger & More)

  2. InfluxDB

    InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.

    InfluxDB logo
  3. Byte Buddy

    Runtime code generation for the Java virtual machine.

    Project mention: Ulyp: Recording Java code execution for faster debugging (Part 1) | dev.to | 2024-10-13

    Currently, Ulyp uses bytebuddy library which does an immense job of handling all the work of instrumentation and makes it extremely easy for all Java developers. The rest is relatively straightforward to implement. The ongoing blogposts will shed a light on how the tool is implemented. Right now, let’s move to action.

  4. Recaf

    The modern Java bytecode editor

  5. Javassist

    Java bytecode engineering toolkit

    Project mention: How to Solve OutOfMemoryError: Metaspace | dev.to | 2024-09-19

    In the above program ‘OOMMetaspace’ class’s ‘main()’ method contains an infinite ‘while (true)’ loop. Within the loop, thread uses open-source library javassist to create dynamic classes whose names start with ‘com.buggyapp.MetaspaceObject’. Class names generated by this program will look something like this: ‘com.buggyapp.MetaspaceObjectb7a02000-ff51-4ef8-9433-3f16b92bba78’. When so many such dynamic classes are created, the Metaspace memory region will reach its limit and the JVM will throw ‘java.lang.OutOfMemoryError: Metaspace’.

  6. Mixin

    Mixin is a trait/mixin and bytecode weaving framework for Java using ASM

    Project mention: LumoSQL | news.ycombinator.com | 2025-05-27

    Very niche but: https://github.com/SpongePowered/Mixin

    It's not really possible to implement in the same way for many other languages, but something like this for source code transformations is probably the kind of thing they're thinking of.

  7. threadtear

    Multifunctional java deobfuscation tool suite

  8. Byteman

    Byteman Project main repo

  9. SaaSHub

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

    SaaSHub logo
  10. yGuard

    The open-source Java obfuscation tool working with Ant and Gradle by yWorks - the diagramming experts

  11. MixinExtras

    Companion library to SpongePowered Mixin with many custom injectors for a more expressive experience.

  12. javaflame

    Create reports for function calls with argument and return values on java. No servers or open connections, just plug the agent and get the results.

  13. Maker

    Cojen/Maker is a lightweight, full-featured, low-level dynamic Java class generator designed for ease of use.

  14. ulyp

    Tracing debugger/profiler for JVM apps

    Project mention: Reverse engineer Spring Web in 5 minutes using a recording debugger | dev.to | 2024-12-17

    Large Java frameworks can be reverse engineered with help of some tools. The article shows how to dig into Spring Web internals with help of ulyp in less than 10 minutes. A developer can observe how framework works inside before diving into source code. This is a part 2 of the ongoing blog series about ulyp. The first part is available here.

NOTE: The open source projects on this list are ordered by number of github stars. The number of mentions indicates repo mentiontions in the last 12 Months or since we started tracking (Dec 2020).

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Java Bytecode Manipulation related posts

  • Introduction to Mixins (2015)

    1 project | news.ycombinator.com | 10 Mar 2025
  • Mixin is a trait/mixin and bytecode weaving framework for Java using ASM

    3 projects | news.ycombinator.com | 27 Dec 2024
  • Ulyp: Recording Java code execution for faster debugging (Part 1)

    2 projects | dev.to | 13 Oct 2024
  • How to Solve OutOfMemoryError: Metaspace

    2 projects | dev.to | 19 Sep 2024
  • Show HN: Javaflame – Simple Flamegraph for your Java application

    3 projects | news.ycombinator.com | 7 Nov 2023
  • Monkey-patching in Java

    2 projects | dev.to | 21 Sep 2023
  • JUnit 5: link tests with task tracker issues

    5 projects | dev.to | 21 Apr 2023
  • A note from our sponsor - SaaSHub
    www.saashub.com | 24 Jun 2025
    SaaSHub helps you find the best software and product alternatives Learn more →

Index

What are some of the best open-source Bytecode Manipulation projects in Java? This list will help you:

# Project Stars
1 bytecode-viewer 15,067
2 Byte Buddy 6,525
3 Recaf 6,478
4 Javassist 4,193
5 Mixin 1,579
6 threadtear 925
7 Byteman 497
8 yGuard 418
9 MixinExtras 368
10 javaflame 91
11 Maker 59
12 ulyp 25

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