Procyon review

Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

Procyon is an open-source suite of Java metaprogramming tools centered on decompiling Java bytecode into Java source. It is suited to developers working with class files, JAR files, Java types, bytecode analysis, reflection, and code generation. The decompiler can run as a standalone JAR or through a Java API, making it relevant for both command-line workflows and applications that need programmable access to decompilation results.

Its main strength is output and API flexibility. Procyon supports Java source, raw bytecode, and bytecode AST output, while accepting class-file and JAR inputs. The published feature set includes handling for lambdas, annotations, records, switch expressions, and sealed types. Beyond decompilation, the toolkit includes reflection and runtime code-generation APIs, expression trees, and experimental compiler tooling. These capabilities make it more useful for program analysis and metaprogramming than a tool limited to source reconstruction.

Procyon is available as free open-source software, with no paid tier described in its published project details. That model fits developers who want a focused Java tool they can invoke from the command line or integrate through code. Its scope is narrower than a broader reverse-engineering environment: native code is outside its stated focus, and no verified debugger, plugin system, or integrations are part of the listed offering. The decompiler is also described as experimental, with v0.6.0 shown as the latest release. Choose Procyon for programmable Java bytecode work; choose another category tool when debugging, ecosystem integrations, or native-code support is central.

Procyon pros and cons

• Where it wins
  • Free, open-source Java decompilation
  • Java, raw bytecode, and AST output
  • CLI and programmatic API support
• Where it doesn't
  • Focused on Java rather than native code
  • No verified debugger, plugins, or integrations
  • The decompiler is described as experimental

Procyon fact sheet, pricing and score →

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Last updated 7 Oct 2026 · How we research and update