Method overloading not working with different parameters [duplicate]

Question

Why isn't this allowed and treated as same signature?

public Object myMethod(Map<String, String[]> values) {
   return this;
}

public Object myMethod(Map<String, String> values) {
   return this;
}

Answer 1

The urban myth answer is:

Because type erasure causes the generics information to be lost. At runtime, those methods appear identical.

Map<X, Y> becomes just Map.

However, the actual answer appears to be more complex. See this excellent answer from a duplicate question. The compiler is actually quite capable of selecting the correct overloaded method given the supplied arguments, however the requirement to support legacy non-generics-aware code has forced the javac developers to forbid it.

Answer 2

This is because of Type Erasure. Type Erasure removes most of the generics information at compile time. So above code after compilation would be

public Object myMethod(Map values) {
   return this;
}

public Object myMethod(Map values) {
   return this;
}

So both the methods are identical at runtime.