public class Pet
{
   private String name;
   private int agressiveness;
   ...

   // some public methods
}

public class Dog extends Pet
{
	// class stuff
}

public class Cat extends Pet
{
	// class stuff
}

public class Collie extends Dog
{
	// class stuff
}

public class Poodle extends Dog
{
	// class stuff
}


public class Kennel
{
   public void giveBath( Pet pet )
	{ /* code here */ }
}

public class KennelDemo
{
  public static void main (String[ ] args )
  {
	Kennel myKennel = new Kennel( );
	Pet myPet = new Pet( );
	Dog myDog = new Dog( );
	Cat myCat = new Cat( );
	Collie myCollie = new Collie( );
	Poodle myPoodle = new Poodle( );


	myKennel.giveBath( myPet );
	myKennel.giveBath( myDog );
	myKennel.giveBath( myCat );
	myKennel.giveBath( myCollie );
	myKennel.giveBath( myPoodle );
}