OOP Concepts in Java_Revision

What is a class in object-oriented programming?

• A class is a collection of data without methods.

• A class is a blueprint for creating objects that defines properties and methods.

• A class is a function that executes code.

• A class is a type of variable in programming.

Which of the following is an example of an object?

• A table

• A chair

• A car

• A computer

What is the purpose of a constructor in a class?

• The purpose of a constructor in a class is to initialize objects.

• To create static variables in a class.

• To delete objects from memory.

• To define methods in a class.

How do you clone an object in Java?

• Use the copy constructor method.

• Implement the Cloneable interface and use the clone() method.

• Call the Object.copy() method.

• Serialize the object to a file.

What method is used to create a copy of an object?

• replicate function

• copy constructor

• duplicate method

• clone or copy method

What is single inheritance?

• Single inheritance is when a class inherits from one and only one parent class.

• Single inheritance allows multiple parent classes.

• Single inheritance is when a class inherits from no parent class.

• Single inheritance is a feature of functional programming only.

What is multiple inheritance?

• Single inheritance from one parent class

• Inheritance that allows classes to share methods only

• Multiple inheritance is when a class can inherit from multiple parent classes.

• A method of combining multiple classes into one

Which keyword is used to inherit a class in Java?

• implements

• inherits

• subclass

• extends

What is an interface in Java?

• An interface is a collection of objects that can be instantiated.

• An interface is a class that can contain method implementations.

• An interface in Java is a reference type that defines a contract for classes to implement.

• An interface is a type of variable that holds data.

How do you implement an interface in a class?

• Use the 'inherits' keyword to implement an interface.

• Define interface methods without implementing them.

• Use the 'extends' keyword in the class declaration.

• Use the 'implements' keyword in the class declaration and define all interface methods.