Frequently Asked Questions

• Why does samples/swing2.rb take so long to start?

JRuby currently is very slow at including large classes (classes which expose many methods). We have a patch almost working which will speed up load time of large classes dramatically. On 1GHz P3 laptop the load time for sample2.rb goes from approximately 2 minutes down to 5 seconds. Expect this patch to land for JRuby 0.8.3

• I extended a java class within Ruby and passed an instance of the extended class to a Java method and it does not invoke an overridden method

This is a bug that we are working on. With any luck this will work for 0.8.3. Note: Even though a java consumer will not see this method a ruby consumer WILL see this overriden method.

• I want to extend/instantiate an abstract class within Ruby

This is currently not possible. At some future point we may support this, but it requires generating bytecode to solve. A work-around to this problem would be to define a concrete implementation of the abstract class and extend that.

• How can I load Ruby (C version) native shared libraries in JRuby

You cannot now and you never will be able to. However, we are slowly making our own versions in Java for modules which should be in a standard Ruby distribution. For external libraries not distributed with Ruby you will always be out of luck.