I have read a lot about the Java class loading process lately. Often I came across texts that claimed that it is not possible to add classes to the classpath during runtime and
@Jen I don't think your experiment can prove your theory, because it is more about object instantiation: your printline happens when an object of this class is instantiated, but not necessarily telling that JVM knows your code, the class, just when it is instantiating.
My opinion is that all Java classes are loaded when JVM is up, and it is possible to plug in more classes into JVM while it is running: this technique is called: Hot deployment.