jSparrow vs OpenRewrite

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.

OpenRewrite is an open-source ecosystem for automated code refactoring, aimed at updating code and reducing technical debt. It represents code as Lossless Semantic Trees, applies transformations, and prints the result back into source code for review. Its recipes cover framework migrations, security fixes, and style consistency, and can be written in YAML, Refaster templates, or Java. Maven and Gradle plugins run recipes locally as part of builds, one repository at a time. The Maven plugin offers a dry run that reports potential changes and writes diff files; recipes run only when explicitly activated by name. Documented support includes Java, Kotlin, and Groovy, plus formats such as HCL, JSON, Properties, Protobuf, TOML, XML, and YAML. Framework coverage includes Spring, Quarkus, and Micronaut. The recipe index lists 4,183 recipes across modules. Core and language libraries use Apache License 2.0, but some recipes have other licensing terms. Core is free; some artifacts require authenticated repository access, and some recipes require a Moderne subscription.