javalang

javalang is an open-source Python library that provides a parser for Java source code and a convenient, Python-friendly representation of its syntax. It reads Java source and converts it into an abstract syntax tree (AST) consisting of nodes defined in the javalang.tree module, such as CompilationUnit, ClassDeclaration, MethodDeclaration, FieldDeclaration, and VariableDeclarator. The library also includes a tokenizer for breaking Java source into tokens. The primary entry points are available under the javalang.parse and javalang.tokenizer packages. The parse function can parse entire sources into a tree, and there are helpers to parse expressions or types in isolation.

Applications of javalang include static analysis, code navigation, tooling, and educational demonstrations of Java syntax within Python environments. Because javalang is implemented in pure Python, it is portable and easy to install via package managers such as pip. It is a lightweight solution intended for parsing and analysis tasks, rather than as a full compiler or IDE backend.

Limitations should be noted. javalang is a reference-style parser and may not support every feature of all Java versions or the latest language changes. Users should verify compatibility with their target Java version and features, such as generics, annotations, or complex nested constructs. It is best suited for tasks that require extracting structure from Java sources, such as extracting class hierarchies, method signatures, or import usage, rather than performing full semantic analysis or compilation.

In summary, javalang provides a practical, Python-based means to parse Java code into an accessible AST, enabling lightweight analysis and tooling within Python ecosystems.