JAVA CONCEPTS

Important Java Mcq 1

The mechanism of designing a new class based on one or more existing classes is called?

a. Polymorphism

b. Inheritance

c. Abstraction

d. Encapsulation

Answer:

b. Inheritance

Explanation

Inheritance in Java is a mechanism in which one object acquires all the properties and behaviors of a parent object. It is an important part of OOPs (Object Oriented programming systems). The idea behind inheritance in Java is that you can create new classes that are built upon existing classes.

Which keyword is used to import a package from the Java API library?

a) lib b) package c) getlib d) import Answer d) import

Which of the following is not a valid interface?

a. ResultSet b. DriverManager c. Statement d. Connection Answer: b. DriverManager Explanation: DriverManager is a class that acts as an interface between users and Drivers. It

All subclasses are a subtype in object-oriented programming.

a) True b) False Answer b) False Explanation: A subtype is something that is substituted for and behaves as its parent type. All subclass may

Which statement is true for object code?

i) It is used as its fundamental building block ii) Similar objects are classified using a concept of class iii) Polymorphism and abstraction are not