Page 369 - Computer_Science_F5

handle multiple inheritance,
Computer Science 3. How do interfaces provide
and why is it achieved
differently than in other
programming languages?
FOR ONLINE READING ONLY
a way to achieve multiple
inheritance in Java? Explain
the role of interfaces in
defining contracts for classes
and how classes implement
interfaces to fulfill those
contracts.
4. Discuss the diamond problem
in the context of multiple
inheritance and explain how
Java’s interface approach
avoids this issue. Provide
an example to illustrate how
interfaces help resolve the
diamond problem.
5. Describe the concept of
abstract classes and how
they relate to inheritance and
interfaces in Java. Explain
when it’s appropriate to
use abstract classes versus
interfaces in your Java
programs.
6. Discuss the importance of
polymorphism in Object-
Oriented programming
and how inheritance and
interfaces contribute to
achieving polymorphic
behavior in Java. Provide
examples to demonstrate
polymorphism in action
using inheritance and
interfaces.
Computer Science Form 5.indd 360
Abstraction in Java
Abstract classes
Abstract classes are classes that cannot be
instantiated and may contain abstract methods.
They serve as blueprints for other classes and
can define common behavior for subclasses.
In other words, abstract class is a restricted
class that cannot be instantiated directly, but
can only be accessed by inheriting it from
another class.
Abstract method
An abstract method is a method defined in
an abstract class. It serves as a placeholder
for methods that must be implemented by
subclasses. It can only be used in an abstract
class, and it does not have a body. The body is
provided by the subclass. Abstract classes are
declared using the “abstract” keyword. They
can have both abstract and concrete methods.
Abstract classes cannot be instantiated but can
be subclassed. Subclasses of abstract classes
must implement all abstract methods.
Program Example 5.26:
Java program to show abstract class
// Abstract class
abstract class Animal {
// Abstract method (does not have a body)
public abstract void animalSound();
// Regular method
public void sleep() {
System.out.println(“Zzz”);
}
}
// Subclass (inherit from Animal)
class Pig extends Animal {
public void animalSound() {
360
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