View source for JRuby

{{implementation|Ruby}}
{{infobox begin}}<lang ruby>p RUBY_ENGINE
# => "jruby"</lang>{{infobox end}}

JRuby is an implementation of Ruby that runs inside the [[runs on vm::Java Virtual Machine]] and can call Java libraries from Ruby code. JRuby 9.2.x approximates to Ruby 2.5.x.

JRuby has preemptive concurrency like Java; each Ruby Thread is a Java Thread. JRuby can run multiple threads in parallel on multiple CPUs, if the JVM can do so. [[MRI]] has a Global VM Lock and can run these threads on only one CPU. In contrast, JRuby can never fork processes; MRI can fork with some platforms.

JRuby implements the interpreter and most of the core library in [[implemented in language::Java]]. The standard library is a mix of Java and Ruby.

* http://jruby.org