This is an article on IBM web site preview what is coming in Java 7.
Taking the JAM out of the JAR
Java 7 could fix the most long-standing source of irritation to Java developers: the various class loaders and associated classpaths. Sun is taking another whack at this problem with the Java Module System. Instead of a .jar file, data will be stored in a .jam file. This is a sort of "superjar" that contains all the code and metadata. Most importantly, the Java Module System will support versioning for the first time, so you can say that a program needs Xerces 2.7.1 but not 2.6. It will also allow you to specify dependencies; for instance, to say that the program in the JAM requires JDOM. It should also enable you to load one module without loading them all. Finally, it will support a centralized repository that can provide many different versions of many different JAMs, from which applications can pick the ones they need. If the JMS works, jre/lib/ext will be a thing of the past.
Finally, Java developers admit the CLR assembly model is better:)