The Ultimate JD-GUI Guide: Download Java Decompiler for JD Decompiling

Stuck with a Jar file without source code ? want to regenerate source code from JAR / .CLASS files. Here is the quick guide help you decompile Java .class files and jars using Java Decompiler JD.

1. Java Decompiler JD Overview.

Java Decompiler JD is a decompiler for the Java programming language. JD Java Decompiler is provided as a GUI Tool, as Core Library and as a plugin for the Eclipse, IntelliJ IDE tools. All of JD-Core, JD-GUI & JD-Eclipse are open source projects released under the GPLv3 License.

If you are a Java developer, you may have come across the term JD-GUI or JDGUI. JD-GUI is a popular Java decompiler that allows you to reverse engineer compiled Java code into source code.

This can be incredibly useful when you need to understand how a particular Java program works or when you need to debug an issue. In this article, we will provide a JD-GUI guide and show you how to download JD-GUI for your Java decompiling needs.

What is JD-GUI?

JD-GUI is a free, open-source Java decompiler that allows you to decompile Java class files into source code. It was developed by Emmanuel Dupuy and is available for Windows, macOS, and Linux operating systems.

JD-GUI is written in Java, which means it can run on any platform that supports Java. JD-GUI is often used by Java developers to inspect Java class files and understand how they work.

Why Use JD-GUI?

There are several reasons why you may want to use JD-GUI. Firstly, JD-GUI allows you to inspect Java class files and understand how they work. This can be useful when you are trying to understand how a particular Java program works or when you need to debug an issue. Secondly, JD-GUI can help you to recover lost or damaged source code.

If you have lost the source code for a Java program, JD-GUI can help you recover it by decompiling the class files. Finally, JD-GUI can be used to analyze Java code and identify potential vulnerabilities.

If you want to know more about Java Decompiler JD, you can go through Java Decompiler Official Website.

2. How to Download JD-GUI

You can download java decompiler from JD Project Official site. Go to java decompiler github https://java-decompiler.github.io/ and download the Java Decompiler JD based on your operating system. You can download java decompiler jar core libray or java decompiler command line, java decompiler GUI or java decompiler eclipse plugin based on your requirement.

• jd-gui-1.6.6.jar

  JD GUI CORE Library

• jd-gui-1.6.6-min.jar

  JD GUI CORE Library Minimized

• jd-gui-1.6.6.rpm
  jd-gui-1.6.6.deb

  JD GUI Linux

• jd-gui-osx-1.6.6.tar

  JD GUI OSX

• jd-gui-windows-1.6.6.zip

  JD GUI Windows

3. Install Java Decompiler On Windows

On windows, you can use Java Decompiler GUI, a user friendly GUI interface that lets you open any Jar / class file and decompiles accordingly. If you are a eclipse user and would like to have java decompiler as a eclipse java decompiler plugin you can simply install eclipse plugin (steps to install plugin are given below). And if you dont want to use any of these you can use Java Decompiler Commandline a simple command line interface to decompile java class file.

3.1 Install Java Decompiler GUI On Windows

On windows, installation is simple, all you have to do is unzip the downloaded file and execute the jd-gui.exe file.


Note: JD GUI Java Decompiler requires Java 1.8, if not installed you might endup with "This application requires Java Runtime Environment 1.8.0" Error.

			
			

error launching 'jd-gui' no suitable java version found on your system! 
this program requires java 1.8+ 
make sure you install the required java version.
			
			
			

Please refer how to install Java Openjdk 1.8 on Windows for detailed steps to install java.

Java Decompiler configuration and Class Path Settings

This is required only if java is not recognized even after java installation. Make sure that "JAVA_HOME" and "PATH" environment variables point to the installed java binaries.

Verify Java Decompiler Installation

Once the Java Decompiler JD Download and installation is complete, we can verify by clicking on jd-gui.exe file. You should be able to see decompiled .class file.

Congratulations !!! Now you have installed Java Decompiler Successfully.

3.2 Installing Java Decompiler Eclipse Plugin

Along with JD GUI, Java JD Decompiler also provides eclipse plugin to decompile .class files. This plugin would be handy for eclipse IDE java developers. If you are new to eclipse / would like update to latest available version of eclipse please refer How Install Eclipse .

Once you install the eclipse, you can download the JD Decompiler binaries from JD Decompiler official website https://java-decompiler.github.io/ . Once the binaries are downloaded, extract the content to any folder in local. Then follow the below steps to install JD Decompiler Plugin in Eclipse.

Steps to install Java Decompiler Eclipse Plugin.

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Here are the quick steps to install Java Decompiler Plugin in Eclipse.

• Launch eclipse and goto Help -> Install new Software.


• Drag and drop the downloaded Java Decompiler zip file on to the Dialog window.


• Check Java Decompiler Eclipse Plug-in.





• Click on "Next" and "Finish" buttons.
• You might get a security warning in eclipse to install the software. Select "Install Anyway" and proceed with installation.





• After the software is installed, a pop up comes asking to restart the eclipse. Select "Restart Now" and proceed.





• Once eclipse restarts, goto Windows -> Preferences. You could see Drools under preferences. This confirms the Drools plugin installation in eclipse.

3.3 Java Decompiler Core

You can use Jd java decompiler core jar, to decompile a class or jar file programmatially.

		 
ClassFileToJavaSourceDecompiler decompiler = new ClassFileToJavaSourceDecompiler();

decompiler.decompile(loader, printer, "path/to/YourClass");

String source = printer.toString();
		 
		 

Refer https://github.com/java-decompiler/jd-core for details.

4. JD-GUI alternatives

JD-GUI is a powerful Java decompiler that is widely used by Java developers. However, there are other alternatives available that can also be used for decompiling Java code. Here are some of the most popular JD-GUI alternatives:

1. Procyon: Procyon is a free, open-source Java decompiler that is known for its fast performance and support for Java 8 features. It is easy to use and supports multiple input and output formats.
2. Fernflower: Fernflower is another popular Java decompiler that is free and open-source. It is known for its ability to decompile obfuscated code and its support for Java 8 features.
3. Bytecode Viewer: Bytecode Viewer is a Java decompiler that is designed for analyzing and decompiling Java class files. It has a user-friendly interface and is available for Windows, macOS, and Linux operating systems.
4. JAD: JAD is a Java decompiler that has been around for many years. It is free to use and supports multiple input and output formats. However, it has not been updated in a while, so it may not support the latest Java features.
5. Krakatau: Krakatau is a Java decompiler that is designed for advanced users. It allows you to decompile Java code at the bytecode level, which can be useful for analyzing and understanding how Java programs work.

These are just a few of the many JD-GUI alternatives that are available. Each of these tools has its own strengths and weaknesses, so it is important to choose the one that best fits your needs.

5. Summary

Over all, JD Java decompiler is a simple tool that decompiles java class files more efficiently. For developers, Jd decompiler plugin helps to decomplile third party jar class files in eclipse at easy. For all JD Java Decompiler related issues and support, please visit https://github.com/java-decompiler/jd-eclipse/issues for eclipse plugin and https://github.com/java-decompiler/jd-gui/issues for JD GUI related issues.

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