Java Method Confusion

Question

In Java, when for example you say string1.compareTo(string2), how is the compareTo method accessing the string1. I see the method takes in the second string but how does it compare it to the first if it is not getting passed along?

Answer 1

compareTo() is a member function of Class String, this means that for invoking this function you need an Object of Type String. So when you say string1.compareTo(string2) , this means that you are invoking compareTo() function on the String object 'string1' and passing 'string2' as the argument.

Answer 2

I think this little 'illustration' could help you

Class String {

    public int CompareTo(String string2)
    {
        if (this==string2) return 1; //The == is completely wrong here but it gives you an idea on how it works
        else return 0;
    }

}

When you call string1.CompareTo(string2); in the method, this will reference the object itself, so here it references string1