ClassCastException when casting to the same class

Question

I have 2 different Java projects, one has 2 classes: dynamicbeans.DynamicBean2 and dynamic.Validator.

On the other project, I load both of

Answer 1

I got the A2AClassCastException problem when trying to create a List of objects from XML using Apache Commons Digester.

List templates = new ArrayList();
Digester digester = new Digester();
digester.addObjectCreate("/path/to/template", MyTemplate.class);
digester.addSetNext("/path/to/template", "add");
// Set more rules...
digester.parse(f); // f is a pre-defined File

for(MyTemplate t : templates) { // ClassCastException: Cannot cast mypackage.MyTemplate to mypackage.MyTemplate
    // Do stuff
}

As stated above, the cause is that the digester doesn't use the same ClassLoader as the rest of the program. I ran this in JBoss, and it turned out that commons-digester.jar was not in JBoss's lib directory, but rather in a webapp's lib directory. Copying the jar into mywebapp/WEB-INF/lib also solved the problem. Another solution was to casll digester.setClassLoader(MyTemplate.class.getClassLoader()), but that feels like quite an ugly solution in this context.