Method has the same erasure as another method in type

Question

Why is it not legal to have the following two methods in the same class?

class Test{
   void add(Set ii){}
   void add(Set ss){}         


        

Answer 1

The problem is that Set<Integer> and Set<String> are actually treated as a Set from the JVM. Selecting a type for the Set (String or Integer in your case) is only syntactic sugar used by the compiler. The JVM can't distinguish between Set<String> and Set<Integer>.