Java Puzzle – Method Overloading Part 2

This is with reference with previous block, but next level.

Program

public class OverloadingPuzzle {
public void display(Object obj){
System.out.println("Object version");
}

public void display(String str){
System.out.println("String Version");
}
public void display(Integer str){
System.out.println("Integer Version");
}

public static void main(String[] args){
OverloadingPuzzle obj = new OverloadingPuzzle();
obj.display(null);
}
}

Now I am confused, will it print String Version or Integer Version.

Output

like me Compiler is also confused here, there will be compilation error

Uncompilable source code - reference to display is ambiguous, both method display(java.lang.String) in testproject.OverloadingPuzzle and method display(java.lang.Integer) in testproject.OverloadingPuzzle match