Automatic Call of toString()

Actually, System.out.println() can deal with several types of parameters, and one of them is reference to a String. No version of System.out.println() was written to use a Point reference, however. So the following does not look like it will work:

Point a = new Point();  // a is a Point reference

System.out.println( a ); 
                    |
                    +--- should be String reference 

However, it does work, for the following reason:

When a parameter should be a String reference, but is a reference to another type of object, Java calls the object's toString() method to create a String and then uses the resulting String reference.

All objects (of any type at all) have their own toString() method, so this trick works with any object.