Consider to use asserts in Java code

[mikir]

Currently, we use @SuppressWarning("unchecked") in Java code. For example:

    @SuppressWarnings("unchecked")
    private <T extends AstNode> void addReferencedSymbolObject(Set<T> referencedObjectList,
            Class<? extends AstNode> elementClass)
    {
        if (symbolObject != null && elementClass.isInstance(symbolObject))
            referencedObjectList.add((T)symbolObject);
    ...

Investigate how to improve such constructs. Consider to use Java asserts which are disabled by default. It could be enabled in Ant by the following java task parameter:

    <jvmarg value="-enableassertions"/>