Data verified May 2026
ADYour product here. Reach security decision-makers.Launch a campaignFernflower Description
Fernflower is the first actually working analytical decompiler for Java and probably for a high-level programming language in general. Naturally, it is still under development. Please send your bug reports and improvement suggestions to the issue tracker. Fernflower is licensed under the Apache Licence Version 2.0. Running from the command line: java -jar fernflower.jar [-<option>=<value>]* [<source>]+ <destination>. * means 0 or more times, + means 1 or more times. <source>: file or directory with files to be decompiled. Directories are recursively scanned. Allowed file extensions are class, zip, and jar. Sources prefixed with -e= mean 'library' files that won't be decompiled but taken into account when analyzing relationships between classes or methods. Especially renaming of identifiers (s. option 'ren') can benefit from information about external classes. <destination>: destination directory. <option>, <value>: a command-line option with the corresponding value (see 'Command-line options' below). Examples: java -jar fernflower.jar -hes=0 -hdc=0 c:\Temp\binary\ -e=c:\Java\rt.jar c:\Temp\source\ java -jar fernflower.jar -dgs=1 c:\Temp\binary\library.jar c:\Temp\bin
Fernflower FAQ
Common questions about Fernflower including features, pricing, alternatives, and user reviews.
Fernflower is Fernflower is an analytical decompiler for Java with command-line options and support for external classes. It is a Security Operations solution designed to help security teams with Binary Analysis.
Fernflower is a free Security Operations tool. This makes it accessible for organizations of all sizes, from startups to enterprises. Visit https://github.com/fesh0r/fernflower/ for download and installation instructions.
Popular alternatives to Fernflower include:
1.Attify Offensive IoT Exploitation - Private training course for IoT device pentesting and exploitation (Commercial)
2.Nightwing DejaVM - Whole-system emulation environment for software dev, debugging, testing & security (Commercial)
3.Zenyard RE Agent - AI agent for in-depth binary analysis and reverse engineering assistance. (Commercial)
4.Boomerang Decompiler - An open source machine code decompiler that converts binary executables into readable C source code across multiple architectures and file formats. (Free)
5.Shellcode2PE - A Python script that converts shellcode into a PE32 or PE32+ file. (Free)
Compare these tools and more at https://cybersectools.com/categories/security-operations
Fernflower is for security teams and organizations that need Binary Analysis. It's particularly suitable for small to medium-sized teams looking for cost-effective solutions. Other Security Operations tools can be found at https://cybersectools.com/categories/security-operations
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