JAVA CONCEPTS

Important Java Mcq 1

Which of these interfaces must contain a unique element?

a) Set

b) List

c) Array

d) Collection

Answer

a) Set

Explanation:

A Set is a collection of items where every item is unique, and it is found in java.util package, thus option A is correct!

Every Java application is composed of at least one?

a. Local variable b. Instance variable c. Public class declaration d. Imported class Answer: c. Public class declaration Explanation In any Java program there must

Which interface restricts duplicate elements?

a) Set b) List c) Map d) All of these Answer: a) Set

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

When saving a java source file, save it with an extension of

a. .class b. .java c. .py d. .asp Answer: b. .java Explanation: We always save java files with the extension .java.