JRuby is an alternate implementation of the Ruby programming language. It is also an embedded language for the Java Virtual machine (JVM). On both of these fronts, we have a set of limitations that a user should be aware of.

When we outline each limitation, we will note whether we think that the limitation is likely to go away and JRuby matures. In some cases, we cannot implement features because the underlying JVM does not allow it. In other cases, it is simply not implemented yet.

Ruby conformance Limitations

This section reflects known incompatibilities between Ruby and JRuby. It is by no means comprehensive. It just reflects larger issues we are aware of. The fact that Ruby does not have a language specification also makes having an exact delta between the two implementations impossible.