Overloading query

[Abhinaba Basu]

My code is given below:

public class Main{
    
    
public static void main(String[] args) {
    
  
     
    new Main().A(null);
    
 
}


public void A(String str){
    System.out.println("String");
}

public void A(Object obj){
    System.out.println("Object");
}



}

And it is printnig "String"

And my next code is give below:

public class Main{
    
    
public static void main(String[] args) {
    
  
     
    new Main().A(null);
    
 
}


public void A(String str){
    System.out.println("String");
}

public void A(StringBuffer obj){
    System.out.println("StringBuffer");
}



}

Why it is doing like this? Can anybody explain me?

[marc weber]

See if this helps: Most specific method.

[vidya sagar]

Normally in this scenario,More appropriate matching method will be called.

In the First Case,String is more appropriate. so the method with string argument is called.

But in the Second Case,String and StringBuffer is in same level so the compiler cannot know which one to choose.So it throws ambiguous error.