Inheritance - Java - page 452

if (object1.getClass() == object2.getClass())
System.out.println("Same class.");
else
System.out.println("Not the same class.");

will output Same class if object1 and object2 were created with the same class when
they were created using new , and output Not same class otherwise.
Our final version of the method equals is shown in Display 7.10. Note that we
have also taken care of one more possible case. The predefined constant null can be
plugged in for a parameter of type Object . The Java documentation says that an
equals method should return false when comparing an object and the value null . So
that is what we have done.
On the accompanying CD, the subdirectory improvedEquals (of the directory for
this chapter) has a definition of the class Employee that includes this definition of
equals .

extra code
on CD

Display 7.10 A Better equals Method for the Class Employee

1 public boolean equals(Object otherObject)

2 {

3 if (otherObject == null )

4 return false ;

5 else if (getClass() != otherObject.getClass())

6 return false ;

7 else

8 {

9 Employee otherEmployee = (Employee)otherObject;

10 return (name.equals(otherEmployee.name)

11 && hireDate.equals(otherEmployee.hireDate));

12 }

13 }