Just to further clarify, the existence (or not) an _explicit_ cast operator is not necessary to create an implicit cast that might fail. The dumbest case being due to the contra variant array semantics that say i can do this:

Object[] foo = new String[10] foo[0] = new Integer(1)

which is the type error, even if the reported error is something akin to a "array store error" or something (it's been a long time since i did java programming :D)