java source code parsing with full ast generation (java 1-25 support)
Converts Java source code into a complete Abstract Syntax Tree using a recursive descent parser that handles Java language features from version 1.0 through Java 25 including preview features. The parser generates a hierarchical node structure (CompilationUnit → ClassOrInterfaceDeclaration → MethodDeclaration, etc.) that preserves all syntactic information including comments, annotations, and modifiers. The parsing pipeline tokenizes input, applies grammar rules, and constructs typed AST nodes that can be traversed and manipulated programmatically.
Unique: Supports Java 1-25 with preview features through a metamodel-driven parser generator (javaparser-core-metamodel-generator) that auto-generates AST node classes from a grammar specification, enabling rapid adaptation to new Java language features without manual node class creation
vs alternatives: More comprehensive Java version support (1-25) than ANTLR-based parsers and includes built-in symbol resolution, whereas generic parser generators require separate semantic analysis layers
ast node traversal and visitor pattern implementation
Provides visitor pattern implementations (GenericVisitor, ModifierVisitor, VoidVisitor) that enable traversal and transformation of the AST without modifying the node classes themselves. The visitor pattern allows developers to define custom logic that executes on specific node types (e.g., MethodDeclaration, FieldDeclaration) as the tree is walked. ModifierVisitor enables in-place AST transformation by returning modified nodes, while VoidVisitor supports side-effect operations like analysis and reporting.
Unique: Implements three distinct visitor variants (GenericVisitor for read-only traversal, ModifierVisitor for in-place transformation, VoidVisitor for side-effects) generated from a metamodel, allowing developers to choose the appropriate pattern without boilerplate
vs alternatives: More flexible than tree-walking interpreters because visitors are composable and can be chained; more type-safe than reflection-based AST manipulation because visitor methods are generated with correct node type signatures
annotation processing and metadata extraction
Extracts and analyzes Java annotations from AST nodes, providing access to annotation values, targets, and metadata. Developers can query annotations on classes, methods, fields, and parameters, and extract annotation values (strings, numbers, arrays, nested annotations) for use in code analysis and generation. This enables tools to leverage annotation-driven development patterns and extract configuration from annotated code.
Unique: Provides direct AST-level access to annotations through AnnotationExpr nodes, enabling extraction of annotation values without reflection or runtime processing, making it suitable for static analysis and code generation
vs alternatives: More flexible than reflection-based annotation processing because it works with source code; more complete than regex-based annotation matching because it understands annotation syntax and values
method and field resolution with overload resolution
Resolves method calls and field accesses to their definitions by analyzing method signatures, parameter types, and inheritance hierarchies to determine which overloaded method is being invoked. The resolution system handles method overloading, varargs, type erasure, and inheritance-based method lookup (including interface default methods). It returns ResolvedMethodDeclaration objects that provide access to the method's signature, return type, and declaring class.
Unique: Implements overload resolution that respects Java's method selection rules (exact match, widening conversion, boxing, varargs) and handles inheritance-based lookup including interface default methods, enabling accurate determination of which method is invoked
vs alternatives: More accurate than name-based matching because it considers parameter types and inheritance; more complete than simple signature matching because it handles overloading and method overriding
lexical preservation and comment attribution
Preserves original source formatting, whitespace, and comments during parsing and AST manipulation through a lexical preservation system that tracks token positions and associates comments with AST nodes. When the AST is modified and pretty-printed, the original formatting is maintained where possible, and comments are reattached to their corresponding code elements. This is critical for tools that need to preserve developer intent and code style during transformations.
Unique: Uses a token-position tracking system (Range objects) that maps AST nodes to their source locations and associates comments through proximity analysis, enabling round-trip preservation where code can be parsed, modified, and printed with original formatting intact
vs alternatives: Preserves formatting better than ANTLR-based parsers which typically discard whitespace; more accurate comment attribution than regex-based comment matching because it uses syntactic context
symbol resolution and type inference across compilation units
Resolves Java symbols (types, methods, fields, variables) to their definitions across multiple compilation units using a context-based resolution system (javaparser-symbol-solver-core). The symbol solver uses type resolvers (ReflectionTypeSolver, JavaParserTypeSolver, CombinedTypeSolver) to locate symbol definitions in the classpath, source code, or runtime reflection. It performs type inference on expressions and method calls, handling generics, inheritance hierarchies, and method overloading to determine the exact symbol being referenced.
Unique: Implements a pluggable type resolver architecture (TypeSolver interface) that combines multiple resolution strategies (reflection, source parsing, classpath scanning) through CombinedTypeSolver, enabling resolution across heterogeneous codebases mixing compiled and source code
vs alternatives: More accurate than simple name-based matching because it respects Java scoping rules and inheritance; more flexible than IDE-specific symbol tables because it works with arbitrary codebases without IDE integration
code generation from ast templates and builders
Generates Java source code from AST structures using a builder pattern API (CompilationUnitBuilder, ClassOrInterfaceBuilder, MethodBuilder, etc.) that constructs AST nodes programmatically without parsing. Developers can fluently build AST hierarchies by chaining builder methods, then pretty-print the resulting AST to Java source code. This enables code generation tools to create Java code dynamically based on templates, configurations, or runtime decisions.
Unique: Provides a fluent builder API (CompilationUnitBuilder, ClassOrInterfaceBuilder) that mirrors the AST structure, allowing developers to construct code programmatically without parsing, with type-safe method chaining and automatic node hierarchy management
vs alternatives: More type-safe and discoverable than string-based code generation because builders enforce valid AST construction; more maintainable than template strings because changes to code structure are refactored automatically
ast serialization and deserialization to json
Serializes parsed AST structures to JSON format and deserializes JSON back into AST objects through the javaparser-core-serialization module. This enables AST persistence, transmission over networks, and integration with tools that work with JSON representations of code structure. The serialization preserves all AST node information including types, positions, and metadata.
Unique: Provides bidirectional JSON serialization that preserves all AST node types and metadata, enabling round-trip conversion (AST → JSON → AST) without information loss, unlike generic JSON serialization which would lose type information
vs alternatives: More complete than generic JSON serialization because it preserves AST node types; more efficient than re-parsing because deserialization is faster than parsing for cached ASTs
+4 more capabilities