The following sample code is provided as an example for assertion "Two different methods of a class may not override methods with the same erasure":

class C<T> { T id (T x) {...} }
interface I<T> { Tid(T x); }
class D extends C<String> implements I<Integer> {
   String id(String x) {...}
   Integer id(Integer x) {...}
}

There is an obvious typo in that code: whitespace is omited in the interface method's declaration, between the method's mame and return type.