Java Polymorphism and Interfaces Quiz

A polymorphic reference is one that can refer to _______________ type(s) of object(s).

In Java, polymorphic method binding occurs ____________________.

In Java, a(n) ___________________ is a collection of constants and abstract methods.

Which of the following is true regarding the method call spot.speak() with Animal spot = new Dog();?

What will the following method call a.compareTo(b) return if Object a is larger than Object b?

In order to create a class that implements an interface, the __________________ keyword is used.

What will happen if you try to call a.wagTail() when a is declared as Animal a = new Dog();?

The commitment to execute certain code to carry out a method invocation is referred to as ______________.

It is possible to create an object by instantiating the Animal interface.

A parameter to a method can be polymorphic.

An interface cannot declare any instance variables.

If a class implements an interface, it cannot extend another class.

How does inheritance support polymorphism?

What is the difference between a class and an interface?

Describe the Comparable interface.

Polymorphism

Polymorphic reference can refer to multiple types of objects.
In Java, polymorphic method binding occurs at run-time, meaning the method invoked is determined by the object’s actual type.

Interfaces

An interface in Java consists of constants and abstract methods.
A class implementing an interface uses the "implements" keyword.

Method Overriding

If a Dog class overrides a method from a parent Animal class, calling spot.speak() will invoke the Dog's overridden method.
If the Dog class implements the Animal interface with an additional method wagTail, trying to call a.wagTail() will result in a compile-time error because wagTail() is not defined in the Animal interface.

Object Comparison

The compareTo method will return a number greater than 0 if the first object is larger than the second, zero if they are equal, or less than 0 if the first is smaller.

Binding and Instantiation

Binding refers to the commitment to execute certain code for a method invocation.
It is false that an object can be instantiated from an interface; interfaces cannot be instantiated.
It is true that methods' parameters can be polymorphic, allowing for various object types.

Class vs. Interface

A class can be instantiated, while an interface cannot.
A class that implements an interface can still extend another class.

Comparable Interface

The Comparable interface includes a method called compareTo that returns three possible values: greater than 0, equal to 0, or less than 0, indicating the comparative result between objects.

Test your understanding of Java polymorphism and interfaces with this quiz. It covers key concepts such as polymorphic references, method binding at run-time, and the structure of interfaces in Java. Perfect for any Java programming student!