问题
why so many different ways to include Java classes into JRuby? What are the differences? Which one should I use?
回答1:
You can find quite a few examples about working with Java classes at:
https://github.com/jruby/jruby/wiki/CallingJavaFromJRuby
It states, that you should use java_import instead of import due to the JRUBY-3171 bug.
Also include_class is or will be deprecated (JRUBY-3797) in favor of java_import.
Currently java_import is the recommended way to import a Java class.
回答2:
import doesn't play well with Rake, so it's discouraged. java_import is the newest, and recommended. include_class has been deprecated. Apart from that they all do the same thing, and are actually aliases of each other.
import is an alias for java_import and java_import calls include_class.
来源：https://stackoverflow.com/questions/2578582/jruby-import-vs-include-vs-java-import-vs-include-class