Discovering Classes and Objects - Beginning Java 7 - page 97

Note setName() invokesthe String class's indexOf() and substring()
methods. You'll learn about these and other String methods in Chapter 4 .

Javaprovidesalittleknowninformationhiding-relatedlanguagefeaturethatletsone
object(orclassmethod/initializer)accessanotherobject's private fieldsorinvokeits
private methods. Listing 2-15 provides a demonstration.

Listing 2-15. One object accessing another object's private field

class PrivateAccess
{

private int x;
PrivateAccess(int x)
{

this.x = x;

}
boolean equalTo(PrivateAccess pa)
{

return pa.x == x;

}
public static void main(String[] args)
{

PrivateAccess pa1 = new PrivateAccess(10);
PrivateAccess pa2 = new PrivateAccess(20);
PrivateAccess pa3 = new PrivateAccess(10);
System.out.println("pa1 equal to pa2:

"+pa1.equalTo(pa2));
System.out.println("pa2 equal to pa3:

"+pa2.equalTo(pa3));
System.out.println("pa1 equal to pa3:

"+pa1.equalTo(pa3));
System.out.println( pa2.x );

}

}

Listing2-15 ' s PrivateAccess classdeclares a private int fieldnamed x .It
also declares an equalTo() method that takes a PrivateAccess argument. The