Java Fundamentals for Students

What is the correct way to declare a variable in Java?

• var variableName int;

• int variableName;

• int: variableName;

• int variableName = 0;

Explain the concept of inheritance in Object-Oriented Programming.

• Inheritance is the process of creating new classes without any relationship to existing ones.

• Inheritance is a method to delete classes in programming.

• Inheritance allows a subclass to inherit attributes and methods from a superclass, promoting code reuse and establishing a class hierarchy.

• Inheritance allows a class to operate independently of other classes.

What is the purpose of the main method in a Java application?

• The main method handles exceptions in Java.

• The main method is responsible for garbage collection.

• The main method is the entry point for a Java application.

• The main method is used for defining classes.

Define encapsulation and its benefits in Java.

• Encapsulation is only about data hiding and has no other benefits.

• Encapsulation in Java is the practice of restricting access to an object's internal state and requiring all interaction to be performed through an object's methods.

• Encapsulation allows direct access to an object's internal state.

• Encapsulation in Java is the same as inheritance.

What is the difference between an interface and an abstract class in Java?

• An interface defines a contract with no implementation, while an abstract class can have both abstract and concrete methods and allows for state.

• An abstract class can only have concrete methods, while an interface can have abstract methods.

• An interface can have state, while an abstract class cannot.

• An interface can extend multiple classes, while an abstract class can only extend one interface.