Spoon is a comprehensive, open-source Java library for source code analysis, transformation, and generation. Developed at INRIA, it provides a complete AST metamodel covering all modern Java constructs (up to Java 25), along with powerful APIs for pattern matching, template-based code generation, static dataflow analysis (with Z3 integration), control flow graph construction, Javadoc parsing, and decompilation. The architecture is modular with submodules for specific tasks (e.g., spoon-dataflow, spoon-smpl for semantic patches, spoon-visualisation). Spoon is used both as a research platform for program analysis and as a practical tool for building custom code transformations, linters, and refactoring tools. The codebase demonstrates high engineering quality with clean separation of interfaces and implementations, extensive use of visitor and factory patterns, and a sophisticated query API.
Etl-engine is a Java-based ETL (Extract, Transform, Load) library designed for high-performance data synchronization. It provides a lightweight, extensible framework built around three core components: Node (data sources/destinations/transformations), Pipe (thread-safe buffered queues for data transfer), and Dataflow (orchestrator for pipeline execution). The library supports various data sources including JDBC databases (PostgreSQL, MySQL, Oracle, ClickHouse, DuckDB) and file outputs, with built-in capabilities for batch processing, automatic error handling/retry, and detailed logging. The architecture follows a producer-consumer pattern using Java's concurrency utilities, enabling efficient parallel data processing. Sample implementations demonstrate common ETL scenarios like database-to-database transfers, conditional data routing, and value transformation.