Access Methods

A class with private data provides access to that data through access methods. An access method is a method which uses the private data of its object and is visible to other classes. Some access methods alter data; others return a value but don't alter data. Here is a main() that uses the access methods of a CheckingAccount object.

class CheckingAccount
{
  private String accountNumber;
  private String accountHolder;
  private int    balance;
  . . . .
}

class CheckingAccountTester
{
  public static void main( String[] args )
  {
    CheckingAccount bobsAccount = new CheckingAccount( "999", "Bob", 100 );

    System.out.println( bobsAccount.getBalance() );
    bobsAccount.processDeposit( 200 );
    System.out.println( bobsAccount.getBalance() );

  }
}

This main() program uses access methods of the CheckingAccount object to change the object's data. This is (usually) the correct way to use an object. The methods of an object know best how to change its instance variables. The idea of private is to enforce this correct use.