A DESCRIPTION OF THE PROBLEM :
When overriding a generic method with a generic parameter the compiler does not match the parent method. It works fine with no or not generic parameters.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to compile the example code. Works fine for get but not for get2.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Compile with "Note: A.java uses unchecked or unsafe operations." (for get and get2)
ACTUAL -
error: A.B is not abstract and does not override abstract method <Y>get2(Collection<String>) in A
        public class B extends A {
               ^
  where Y is a type-variable:
    Y extends Object declared in method <Y>get2(Collection<String>)
A.java:21: error: name clash: get2(Collection<String>) in A.B and <Y>get2(Collection<String>) in A have the same erasure, yet neither overrides the other
                public R<Double> get2(Collection<String> p) {
                                 ^
  where Y is a type-variable:
    Y extends Object declared in method <Y>get2(Collection<String>)
A.java:20: error: method does not override or implement a method from a supertype
                @Override
                ^
Note: A.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
3 errors

---------- BEGIN SOURCE ----------
import java.util.Collection;

public abstract class A {

public abstract class R<T> { }

public abstract <X> R<X> get(String p);

public abstract <Y> R<Y> get2(Collection<String> p);

public class B extends A {

@Override
public R<String> get(String p) {
return null;
}

@Override
public R<Double> get2(Collection<String> p) {
return null;
}
}
}
---------- END SOURCE ----------

FREQUENCY : always