wux1an/fernflowers

Java ☕ reverse engineering tool - Batch decompile the jar package.

fernflowers

Why do I write this?

When decompiling with Jetbrains' fernflower, the program freezes for a particular file or directory and cannot continue. In addition, the CPU usage is not high enough during decompiling, which makes decompilation slow.

So I developed this program based on fernflower to optimize these problems, with the following features

• multi-thread,
• progress bar
• breakpoint continue
• failure record

Usage

java 17 is required

usage: java -jar fernflowers.jar [args]
 -h,--help           help
 -i,--input <arg>    input, the directory to be scanned or a single file path.
 -k,--backup         don't delete the jar file in the output path when '--unzip' is specified
 -n,--thread <arg>   thread, default: 20
 -o,--output <arg>   output, the directory to saved result, default: current path.
 -r,--resume         skip the decompiled files (record in 'decompiled.txt') and continue
 -u,--unzip          unzip the jar file

After running for a period of time, almost all files are decomcompiled successfully, and the progress bar remains stuck, indicating that some jar packages have been decomcompiled incorrectly. You only need to terminate the program by Ctrl + C, and the program will automatically print out the wrong jar package path.

Reference

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