How to decompile a whole Jar file? [closed]

by

2022 update: QuiltMC/quiltflower is the latest most advanced Java decompiler:

Quiltflower is a modern, general purpose decompiler focused on improving code quality, speed, and usability.
Quiltflower is a fork of Fernflower and Forgeflower.

Changes include:

  • New language features (Try with resources, switch expressions, pattern matching, and more)
  • Better control flow generation (loops, try-catch, and switch, etc.)
  • More configurability
  • Better error messages
  • Javadoc application
  • Multithreading
  • Optimization
  • Many other miscellaneous features and fixes

Originally intended just for use with the QuiltMC toolchain with Minecraft, Quiltflower quickly expanded to be a general purpose java decompiler aiming to create code that is as accurate and clean as possible.

If the name sounds familiar it’s because Quiltflower is a fork of Fernflower, the (in)famous decompiler that was developed by Stiver, maintained by Jetbrains, and became the default decompiler in Intellij IDEA.
Fernflower also quickly found its way into many other tools.

Over the past year, Quiltflower has added support for features such as modern string concatenation, a code formatter, sealed classes, pattern matching, switch expressions, try-with-resources, and more. Quiltflower also focuses on the code quality of the decompiled output, and takes readability very seriously.

See output examples.

Runs nice with jbang

https://github.com/QuiltMC/quiltflower/releases/download/1.8.1/quiltflower-1.8.1.jar

Or:

java -jar quiltflower.jar -dgs=1 c:\Temp\binary\library.jar c:\Temp\binary\Boot.class c:\Temp\source\

2009: JavaDecompiler can do a good job with a jar: since 0.2.5, All files, in JAR files, are displayed.

http://java.decompiler.free.fr/sites/default/screenshots/screenshot1.png

See also the question “How do I “decompile” Java class files?”.

The JD-Eclipse doesn’t seem to have changed since late 2009 though (see Changes).
So its integration with latest Eclipse (3.8, 4.2+) might be problematic.

JD-Core is actively maintained.

Both are the result of the fantastic work of (SO user) Emmanuel Dupuy.

2018: A more modern option, mentioned in the comments by David Kennedy Araujo:

JetBrains/intellij-community/plugins/java-decompiler/engine

Fernflower is the first actually working analytical decompiler for Java and probably for a high-level programming language in general.

java -jar fernflower.jar [-<option>=<value>]* [<source>]+ <destination>

java -jar fernflower.jar -hes=0 -hdc=0 c:\Temp\binary\ -e=c:\Java\rt.jar c:\Temp\source\

See also How to decompile to java files intellij idea for a command working with recent IntelliJ IDEA.

2022 update: Florian Wendelborn suggests in the comments

this one works well: jdec.app from Leonardo Santos.

More Related Contents:

  1. How to decompile a whole Jar file? [closed]
  2. Calling java code from c#
  3. How to import a jar in Eclipse?
  4. What causes java.lang.IncompatibleClassChangeError?
  5. Java, Classpath, Classloading => Multiple Versions of the same jar/project
  6. decompiling DEX into Java sourcecode
  7. Add JAR files to a Spark job – spark-submit
  8. Runnable JARs missing Images/Files (Resources)
  9. How to include jar files with java file and compile in command prompt
  10. Eclipse: How to build an executable jar with external jar?
  11. Access restriction: The type ‘Application’ is not API (restriction on required library rt.jar)
  12. Eclipse “Error: Could not find or load main class”
  13. How can I write a Java application that can update itself at runtime?
  14. How to build sources JAR with Gradle?
  15. How to read a file from a jar file?
  16. How to bundle images in jar file
  17. Execute jar file with multiple classpath libraries from command prompt
  18. Run class in Jar file
  19. include external jar when running java -jar
  20. Create an Android Jar library for distribution
  21. Updating .class file in jar
  22. I can run .jar files through cmd, but I cannot double click them [closed]
  23. How to create a .jar file using the terminal
  24. Producing executable jar in NetBeans
  25. Difference between extracting and packaging libraries into a jar file
  26. How to create windows service from java jar?
  27. reading MANIFEST.MF file from jar file using JAVA
  28. How do I unsign a jar?
  29. cucumber throwing java.lang.NoClassDefFoundError: io/cucumber/core/gherkin/FeatureParser
  30. Where should i place my files in order to be able to access them when i run the jar?

Leave a Comment