jSparrow vs Spoon

jSparrow is a Java cleanup and refactoring tool for Eclipse IDE and Maven, running on Linux, macOS and Windows. It lists more than 90 refactorings for Java 1.1 and later, with project-level and batch operation. Diff View compares original and proposed code so changes can be reviewed before application. Markers suggest quick fixes during programming, and the base product includes them at no charge. Interactive rules can replace standard output with logging, rename fields to Java naming conventions and remove unused methods, fields and types. Analysis and refactoring run offline, and the FAQ says code is not sent to external servers or third parties. Internet access is required to persist locked refactorings through the NetLicensing API; offline validation servers are available. The site describes jSparrow as open-source, with no license needed since version 4.20.0. Twenty rules are free; paid licenses are $169 a month or $1,325 a year.

Spoon is a free, open-source library for analyzing, rewriting, transforming, and transpiling Java source code. It parses source files into an abstract syntax tree (AST), then exposes APIs for inspecting and changing that model. Processors can perform source-level static analysis on selected AST element types, while architectural rules can be expressed as AST checks and run as JUnit tests in continuous integration. Transformation facilities cover instrumentation and refactoring, including helpers for local and generic variables and removing deprecated methods. Spoon can also provide shared analysis of binary and source code through CtClass objects as an alternative to Java reflection. The project supports Java source up to Java 25, but runtime requirements vary: Spoon 11.x needs JDK 17 or later, 10.x needs JDK 11 or later, and 9.x needs Java 8. It is available through Java, the command line, Maven, and Gradle, with a dependency JAR on Maven Central. Command-line use requires manual classpath handling and source dependencies specified with --source-classpath. Spoon is an official Inria project and an OW2 consortium member.