Classes and Objects - Java in 60 Minutes a Day - page 101

to whatever object that computePay() was invoked on, which in every case is
the this reference.
The computePay() method actually looks like the following:
public double computePay()
{
return this.salary/52;
}
Notice that the this reference and the dot operator were prefixed to salary.
The compiler adds the this reference for you if you do not explicitly add it
yourself. You can add the this reference if you like, or you can simply let the
compiler do it for you.
For example, in the Employee class, the mailCheck() method accesses the
name and address fields. In each case, the this reference is used, whether you
add it to your code or the compiler adds it. The actual mailCheck() method
looks like the following:
public void mailCheck()
{
System.out.println(“Mailing check to “ +
this.name + “\n” + this.address);
}
Notice that name and address are prefixed with this .
Classroom Q & A
Q: The this reference seems a little confusing. Is it necessary?
A: The this reference is one of those fundamental concepts of OOP
that tends to be confusing the first time you see it. To explain the
need for the this reference, I always try to emphasize the fact that
a field or method cannot be accessed without a reference. The this
reference is the only way a method in a class can access the other
fields or methods of the class.
Q: Why does the compiler add this. automatically?
A: It is strictly for convenience. It would be fairly tedious (although
certainly feasible) to add this. every time it was required in a class.
In a large class, there could easily be hundreds of accesses to the
fields or methods of the class, each requiring the this reference.
For now, keep in mind that the this reference is implicitly being
used when a method in your class accesses a field of the class.
You can also use the this reference as an argument to a method, in which
an object passes a reference of itself to another object.