Java Tricky Programming questions Part 2

Sometime back I wrote an article with 5 java tricky programming questions and my friends liked it a lot. Recently I got two java questions that I will be explaining here.
Java Programming Question 1
What is the output of the below program?

public class Test {

    public static void main(String[] args) {

        method(null);

    }

    public static void method(Object o) {

        System.out.println("Object impl");

    }

    public static void method(String s) {

        System.out.println("String impl");

    }

}

According to java specs, in case of overloading, compiler picks the most specific function. Obviously String class is more specific that Object class, hence it will print “String impl”.
What if we have another method in the class like below:

public static void method(StringBuffer i){         System.out.println("StringBuffer impl");     }

In this case, java compiler will throw error as “The method method(String) is ambiguous for the type Test” because String and StringBuffer, none of them are more specific to others. A method is more specific than another if any invocation handled by the first method could be passed on to the other one without a compile-time type error. We can pass String as parameter to Object argument and String argument but not to StringBuffer argument method

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