Browse free open source Java Compilers and projects below. Use the toggles on the left to filter open source Java Compilers by OS, license, language, programming language, and project status.

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  • 1

    MinGW - Minimalist GNU for Windows

    A native Windows port of the GNU Compiler Collection (GCC)

    MinGW: A native Windows port of the GNU Compiler Collection (GCC), with freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All of MinGW's software will execute on the 64bit Windows platforms.
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    Downloads: 3,267,702 This Week
    Last Update:
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  • 2
    JADX

    JADX

    Dex to Java decompiler

    Command-line and GUI tools for producing Java source code from Android Dex and apk files. Decompile Dalvik bytecode to java classes from APK, dex, aar, aab and zip files. Decode AndroidManifest.xml and other resources from resources.arsc. Deobfuscator included. Be aware, Android Studio can interfere with jadx debugger, so it is better to close it before attaching to the process in jadx. Smali debugger, check wiki page for setup and usage. View decompiled code with highlighted syntax.
    Downloads: 1,506 This Week
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  • 3

    unluac

    A decompiler for Lua 5.x

    unluac is a decompiler for Lua 5.0 through 5.4. It runs on Lua chunks that have been compiled with the standard Lua compiler. It requires that debugging information has not been stripped from the chunk. (By default, the Lua compiler includes this debugging information.) This program is written in Java. A JAR package is available in the downloads section so you don't have to compile it. It runs from the command line and accepts a single argument: the file name of a Lua chunk. The decompiled code is printed to the standard output. Here is an example usage of unluac: java -jar unluac.jar myfile.lua > myfile_decompiled.lua The current version also has pretty good support for Lua 5.0 and Lua 5.1. Support for later versions is also good if the code doesn't use too many gotos.
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    Downloads: 648 This Week
    Last Update:
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  • 4
    Luyten

    Luyten

    An open source Java decompiler Gui for Procyon

    Luyten is an open source Java decompiler GUI for Procyon.
    Downloads: 75 This Week
    Last Update:
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  • 5
    Bytecode Viewer

    Bytecode Viewer

    A reverse engineering suite (decompiler, editor, debugger and more)

    Some of Bytecode Viewer features are that it provides Java Decompiling with Six different decompilers (DJ-GUI/Core, Procyon, CFR, Fernflower, Krakatau, and JADX-Core). Bytecode Decompiling with CFIDE. Android APK integrated with Dex2Jar. Securely launch Java applications and insert hooks via EZ-Injection. Scan for malicious code with the Malicious Code Scanner plugin. Export as DEX, Jar, Class, Zip or Java Source File. Open Android APKs, Android DEX, Java Class Files and Java Jars. (WAR & JSP Support!). Extensively configurable, over 100+ settings! Works seamlessly with all Operating Systems. Integrates BCV into Windows by installing it, it'll associate all .class, .dex and .apk to open with BCV. You can view Jar & APK Resources with ease by APKTool.jar integration. It is 100% free and open sourced under GPL v3 CopyLeft.
    Downloads: 57 This Week
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  • 6
    FernFlower

    FernFlower

    Decompiler from Java bytecode to Java, used in IntelliJ IDEA

    Fernflower is an open-source Java decompiler originally developed by JetBrains that takes compiled Java bytecode and reconstructs readable source code, helping developers understand, debug, and recover lost Java code from .class files. It works by analyzing the structure of bytecode and inferring higher-level constructs like loops, conditionals, generics, and exception handling to produce Java source that is as close as possible to what a human would have written, making it useful for both reverse engineering and educational purposes. Fernflower is integrated into popular Java IDEs and tools where decompilation is needed, and its robust analysis handles a wide range of language features introduced across multiple Java versions. Because it outputs clean, structured, and often compilable code, developers use it for auditing binaries, exploring third-party libraries without source, and recovering parts of legacy systems where source was lost or unavailable.
    Downloads: 48 This Week
    Last Update:
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  • 7
    JSmooth creates standard Windows executable files (.exe) that smartly launch java applications. It makes java deployment much smoother and user-friendly, as it is able to find and run Java VMs by itself, or help the user get one if none are available.
    Downloads: 97 This Week
    Last Update:
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  • 8
    WinXP, Vista, Win7, linux, OpenSolaris native port of the BSD PSPSDK (ps2dev.org), with freely distributable import libraries and header files (DevPaks) for building cross compiled homebrew Sony PSP (PlayStation Portable) applications.
    Downloads: 89 This Week
    Last Update:
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  • 9
    JikesTM is a compiler for the JavaTM language. The Jikes project strives for strict adherence to the Java Language and Java Virtual Machine Specifications. Jikes' most popular feature is it's extremely fast compile speed.
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    Downloads: 126 This Week
    Last Update:
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  • 10
    Jad Java decompiler plugin for Eclipse IDE.
    Downloads: 45 This Week
    Last Update:
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  • 11
    Jasmin is a Java Assembler. It takes ASCII descriptions for Java classes, written in a simple assembler-like syntax. It converts them into binary Java .class class files suitable for loading into a Java Virtual Machine implementation.
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    Downloads: 91 This Week
    Last Update:
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  • 12
    OpenJ9

    OpenJ9

    A Java Virtual Machine for OpenJDK

    A Java Virtual Machine for OpenJDK that's optimized for small footprint, fast start-up, and high throughput. Builds on Eclipse OMR and combines with the Extensions for OpenJDK for OpenJ9 repo. We're not sure which route you might have taken on your way here, but we're really pleased to see you! If you came directly from our website, you've probably already learned a lot about Eclipse OpenJ9 and how it fits into the OpenJDK ecosystem. Eclipse OpenJ9 is an independent implementation of a Java Virtual Machine. "Independent implementation" means it was built using the Java Virtual Machine specification without using any code from any other Java Virtual Machine. The OpenJ9 JVM combines with the Java Class libraries from OpenJDK to create a complete JDK tuned for footprint, performance, and reliability that is well suited for cloud deployments. The original source contribution to OpenJ9 came from the IBM "J9" JVM which has been used in production by thousands of Java applications.
    Downloads: 6 This Week
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  • 13
    SMC - The State Machine Compiler

    SMC - The State Machine Compiler

    Translates state machine into a target programming language.

    SMC takes a state machine stored in a .sm file and generates a State pattern in 14 programming languages. Includes: default transitions, transition args, transition guards, push/pop transitions and Entry/Exit actions. See User Manual for more info.
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    Downloads: 23 This Week
    Last Update:
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  • 14
    Develop with Java 1.5, deploy native executables for windows, linux and mac! SWT, JFace, AWT and Swing is supported.
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    Downloads: 61 This Week
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  • 15
    The Open Fortran Project (OFP) provides a Fortran 2008 compliant parser and associated tools. These tools provide a Java and C API for actions called when parser rules are completed. It also provides Fortran interfaces to the OpenCL runtime (new). IMPORTANT NOTICE: The Open Fortran Project has switched to using a parser based on SDF (Syntax Definition Formalism). Please consider using our new work at https://github.com/OpenFortranProject/ofp-sdf. While the SDF parser is not as advanced as the ANTLR-based parser, it provides much more capabilities, including a term rewriting system for creating a Fortran AST (Abstract Syntax Tree) using Stratego/XT (see http://strategoxt.org) and other custom program transformations. The OFP ANTLR-based parser is no longer under active development.
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    Downloads: 44 This Week
    Last Update:
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  • 16
    The aim of this project is to develope a decompiler for java which is platform independent and has options to obfuscate the class file also. The project takes class file as input and decompiles it and provides the source file.
    Downloads: 26 This Week
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  • 17
    Eclipse Portable [4.6–4.26]

    Eclipse Portable [4.6–4.26]

    Portable version of the multifunctional development platform Eclipse.

    With this portable version of Eclipse, you can develop software directly from your removable mass storage device, even without admin rights. To get started, please visit the Eclipse Portable wiki: https://sourceforge.net/p/eclipse-neon-portable/wiki GitHub: https://github.com/Berny23/eclipse-portable Thank you for over 180,000 Downloads! Please note: A few months ago, I completely switched to Linux (now Arch btw). So, I'll be no longer active creating portable apps for Windows.
    Downloads: 56 This Week
    Last Update:
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  • 18
    IKVM.NET is a JVM for the Microsoft .NET Framework and Mono. It can both dynamically run Java classes and can be used to convert Java jars into .NET assemblies. It also includes a port of the OpenJDK class libraries to .NET.
    Downloads: 9 This Week
    Last Update:
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  • 19
    EJE (Everyone's Java Editor)

    EJE (Everyone's Java Editor)

    Learn Java the easy way!

    EJE is a simple Java editor, perfect to learn Java, without learning a complex development tool. EJE is multi-platform (written in Java), light- weight, user-friendly and have several useful basic features. A good help to start with Java! Supports the study of the Java for Aliens book (www.javaforaliens.com), or other my books (Italian Language) like www.nuovojava.it. You don't need to install the JDK anymore (the runtime is embedded). See the video "How to create the "Hello World App in 20 Seconds" at https://www.youtube.com/watch?v=aKiEAGbEk2k
    Downloads: 19 This Week
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  • 20
    Jar Explorer is a simple, easy-to-use application to browse the contents of jar files. It also includes a class decompiler.
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    Downloads: 15 This Week
    Last Update:
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  • 21
    In this project we aim to develop scheme libraries for developing various web applications (especially servlets and xml-based web services). Our approach is to use jscheme (an open source implementation of scheme in Java) as the core language which allow
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    Downloads: 46 This Week
    Last Update:
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  • 22
    z390 Portable Mainframe Assembler

    z390 Portable Mainframe Assembler

    z390 Portable Mainframe Assembler and Emulator

    z390 Portable Mainframe Assembler and Emulator
    Downloads: 8 This Week
    Last Update:
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  • 23
    JNode is a Java New Operating system Design Effort. JNode is a simple to use and install Java operating system for personal use on modern devices. Any java application runs on it, fast and safe. See our homepage for additional information.
    Downloads: 6 This Week
    Last Update:
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  • 24
    JavaGuard is a general purpose bytecode obfuscator, designed to fit effortlessly into your regular build and testing process, providing peace of mind that your valuable Java code is more secure against decompilation and other forms of reverse engineering
    Downloads: 6 This Week
    Last Update:
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  • 25
    jdec is a Java Decompiler. It can be used to reverse the bytecodes present in a .class File to produce a Java Source File which can be nearly correct or equivalent (Due To different Interpretations) to the original java file.[With UI & command line]
    Downloads: 6 This Week
    Last Update:
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