Does the hashCode method in class Robot below obey the equals/hashCode contract?

If yes, what is bad about the hashCode method?

If no, why does the hashCode method violate the contract?

Also in about 1 sentence, describe an easy way to write a hashCode method for almost any class

class Robot

{

private int serialNumber;

private String name;

public boolean equals(Object x)

{

Robot that = (Robot) x;

return this.serialNumber == that.serialNumber && this.name.equals(that.name);

}

public int hashCode()

{ return 1234; }