In the JRuby case, JRuby compiles Ruby to JVM bytecode. Jython may do the same: rather than create cpython bytecode it may produce JVM bytecode which may be o

In the JRuby case, JRuby compiles Ruby to JVM bytecode. Jython may do the same: rather than create cpython bytecode it may produce JVM bytecode which may be optimized by the JVM. However, I do not know anything about Jython performance and they could not be employing the same tactics as JRuby. With modern Java features like lambdas coming into java 7 and 8 and other interesting languages like Scala, Groovy, etc being written for the JVM I'm sure things have come a long way since the time jython 2.4 was being developed on Java 5/6 and I'm sure the JVM has many more optimizations that dynamic languages may benefit from.