Passing null as a method argument

[Karthik Alva]

Hi, I have a doubt when i pass null as an argument to an overloaded method as in the following code

public void method1(Object o){
System.out.print("Inside Object");}

public void method1(String s){
System.out.print("Inside String");}

static void main (String[]args){
method1(null);}

When this is executed inside string gets printed.


Now if i change the code as follows

public void method1(StringBuffer o){
System.out.print("Inside Object");}

public void method1(String s){
System.out.print("Inside String");}

static void main (String[]args){
method1(null);}

now i get a compile time error complaining of ambuiguity.

is it that if a superclass type is present then the code compiles

[Shweta R Dhaneshwar]

Hi Karthik,
You are right...In the first case when null is passed..the compiler calls the most specific of the two...it calls the method which takes String object argument.In the second case there is no inheritance relationship between String and StringBuffer....the compiler can't decide abt the method call...hence the compile time error.