JetBrains/fernflower

Health v2 · maintenance only

Flags: no_releases

Adoption not part of the score

4371 stars · 728 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Fernflower is an analytical decompiler that converts Java bytecode (class, jar, zip files) back into readable Java source code. It is bundled with IntelliJ IDEA and can also be run standalone from the command line.

Use cases

• decompile a jar file back to java source
• read source of class files when debugging in intellij
• recover lost source code from compiled bytecode
• analyze third-party library internals without source
• reverse engineer java bytecode for security research
• decompile obfuscated java classes from the command line

When to choose

• you need to view or recover Java source from compiled class files
• you work in IntelliJ IDEA and want decompiled code during debugging or navigation
• you want a scriptable command-line decompiler with fine-grained options
• you need a mature, actively maintained Java decompiler

When to avoid

• you need to decompile non-JVM languages or bytecode
• you want a GUI decompiler outside of IntelliJ IDEA
• you need to decompile heavily obfuscated code with perfect fidelity
• you target very old or experimental bytecode formats

Facets

library · maturity maintenance

reverse-engineering parser developer-tools cli reverse-engineering developer-tools programming-languages jvm cli cross-platform decompiler java-bytecode intellij-idea static-analysis jvm

Member repositories

For agents

markdown · JSON · MCP: product_card(name="JetBrains/fernflower")