Java Operators

Java Control Statements

Object Oriented Programming

Java Built-in Classes

Java File Handling

Java Error & Exceptions

Java Multithreading

Java Synchronization

Java Networking

Java Collections

Java Interfaces

Java Data Structures

Java Collections Algorithms

Advanced Java

Java Miscellaneous

Java APIs & Frameworks

Java Class References

Java Useful Resources

Java Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to Core Java. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Q 1 - What is a class in java?

A - A class is a blue print from which individual objects are created. A class can contain fields and methods to describe the behavior of an object.

B - class is a special data type.

C - class is used to allocate memory to a data type.

D - none of the above.

Answer : A

Explaination

A class is a blue print from which individual objects are created. A class can contain fields and methods to describe the behavior of an object.

Q 2 - What is the size of char variable?

Answer : B

Explaination

The char data type is represented by single 16-bit Unicode character.

Minimum value: '\u0000' (or 0)

Maximum value: '\uffff' (or 65,535)

Q 3 - What is the default value of String variable?

Answer : C

Explaination

String variable has default value of null if defined as an instance/static variable.

Q 4 - Which of the following is false about String?

A - String is immutable.

B - String can be created using new operator.

C - String is a primary data type.

D - None of the above.

Answer : C

Explaination

String is a object.

Q 5 - What is Encapsulation?

A - Encapsulation is a technique to define different methods of same type.

B - Encapsulation is the ability of an object to take on many forms.

C - Encapsulation is the technique of making the fields in a class private and providing access to the fields via public methods.

D - None of the above.

Answer : C

Explaination

It is the technique of making the fields in a class private and providing access to the fields via public methods. If a field is declared private, it cannot be accessed by anyone outside the class, thereby hiding the fields within the class. Therefore encapsulation is also referred to as data hiding.

Q 6 - Composition represents

A - HAS-A relationship.

B - IS-A relationship.

Answer : A

Explaination

Holding the reference of the other class within some other class is known as composition. It represents a HAS-A relationship. For example, a Student has a Pen. Here Student class has Pen as its instance variable.

Q 7 - What is composition?

A - Composition is a data structure.

B - Composition is a way to create an object.

C - Holding the reference of the other class within some other class is known as composition.

D - None of the above.