Java Inheritance Concepts

What is inheritance in Java?

• Inheritance in Java refers to the process of creating new classes from existing classes without any relationship between them.

• Inheritance in Java is a mechanism that allows a class to inherit properties only from classes in the same package.

• Inheritance in Java allows a class to inherit properties and behaviors from another class.

• Inheritance in Java is a feature that allows a class to inherit properties from an interface.

Explain the concept of single inheritance in Java.

• In Java, single inheritance refers to inheriting from both a superclass and an interface.

• In Java, single inheritance restricts a class to inherit from only one superclass.

• In Java, single inheritance allows a class to inherit from multiple superclasses.

• Single inheritance in Java means a class can inherit from only one subclass.

How does Java support multiple inheritance?

• Via inheritance chains

• Through interfaces

• Through abstract classes

• By using multiple inheritance keywords

What is the difference between method overloading and method overriding?

• Method overloading is used in inheritance, while method overriding is used in polymorphism.

• Method overloading is specific to interfaces, while method overriding is specific to abstract classes.

• Method overloading involves using the same method name with the same parameters, while method overriding involves using a different method name.

• Method overloading involves multiple methods with the same name but different parameters, while method overriding involves replacing a superclass method in a subclass.

Give an example of hierarchical inheritance in Java.

• Manager extends Employee, Person

• Employee extends Person, Manager

• Employee extends Manager, Person

• Person extends Employee, Manager

What is the 'super' keyword used for in Java?

• Refers to the superclass of the current object instance

• Refers to the subclass of the current object instance

• Used to create new instances of a class

• Used to access private methods of a class

Explain the 'instanceof' operator in Java with an example.

• Example: String str = "Hello"; boolean isString = str instanceof String; // 'isString' will be true since 'str' is an instance of the String class.

• Example: String str = "Hello"; boolean isString = str instanceof Integer;

• The 'instanceof' operator is used to check if a variable is an instance of a class.

• Example: int num = 5; boolean isString = num instanceof String;

What is the purpose of the 'final' keyword in Java inheritance?

• To improve code readability

• To allow multiple inheritance

• To enforce encapsulation

• To prevent method overriding or class extension

Discuss the concept of method overriding in Java with an example.

• Method overloading is the same as method overriding

• Method overriding is only applicable to static methods

• Method overriding is not supported in Java

• Example: public class Animal { public void sound() { System.out.println("Animal makes a sound"); } } class Dog extends Animal { @Override public void sound() { System.out.println("Dog barks"); } } Animal animal = new Dog(); animal.sound(); Output: Dog barks

How does Java prevent diamond problem in multiple inheritance?

• Java restricts classes from implementing multiple interfaces.

• Java allows a class to inherit from multiple classes directly.

• Java allows a class to implement multiple interfaces but inherit from only one class.

• Java enforces the diamond problem in multiple inheritance.