JRuby is an implementation of the Ruby language on the JVM.
JRuby addresses the limitations of standard Ruby by running on the Java Virtual Machine, which enables true parallelism without a global interpreter lock and provides access to the JVM's ecosystem of libraries and concurrency primitives. The implementation aims for completeness and correctness while leveraging JVM performance characteristics. It allows tight integration with Java, enabling Ruby code to use Java classes directly and allowing JRuby to be embedded as a scripting language within Java applications.
Developers should choose JRuby when they need Ruby's expressiveness combined with JVM capabilities, particularly for applications requiring true concurrent execution, access to mature Java libraries, or embedding Ruby in a larger Java system. The tool suits projects that benefit from the JVM's performance optimizations, garbage collection, and monitoring tools. It can serve as a faster alternative to standard Ruby for computationally intensive workloads. The project requires a JRE version 21 or higher and can be installed through standard Ruby version managers or downloaded directly from the JRuby website.
The project maintains multiple active release branches with continuous integration testing across them. Development activity spans multiple time zones with core team members distributed across the EU and US, and the project maintains an active community presence on its chat channel. The codebase receives ongoing updates to track Ruby language developments while maintaining compatibility across supported versions.
