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 - Primitive variables are stored on Stack.

A - True

B - False

Answer : A

Explaination

Primitive variables like int, float are stored on Stack.

Q 2 - What is the size of int variable?

Answer : C

Explaination

The int data type is represented by 32-bit signed two's complement integer,

Minimum value: -231

Maximum value: 231-1

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

Answer : B

Explaination

float variable has default value of 0.0f if defined as an instance/static variable.

Q 4 - Which of the following is true about public access modifier?

A - Variables, methods and constructors which are declared public can be accessed by any class.

B - Variables, methods and constructors which are declared public can be accessed by any class lying in same package.

C - Variables, methods and constructors which are declared public in the superclass can be accessed only by its child class.

D - None of the above.

Answer : A

Explaination

Public access modifier is used to make variables, methods and constructors accessible to any class.

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 - What is JRE?

A - JRE is a java based GUI application.

B - JRE is an application development framework.

C - JRE is an implementation of the Java Virtual Machine which executes Java programs.

D - None of the above.

Answer : C

Explaination

Java Runtime Environment is an implementation of the Java Virtual Machine which executes Java programs. It provides the minimum requirements for executing a Java application.

Q 7 - When static binding occurs?

A - Static binding occurs during Compile time.

B - Static binding occurs during load time.

C - Static binding occurs during runtime.

D - None of the above.

Answer : A

Explaination

Static binding occurs during Compile time.

Q 8 - What invokes a thread's run() method?

A - JVM invokes the thread's run() method when the thread is initially executed.

B - Main application running the thread.

C - start() method of the thread class.

D - None of the above.

Answer : A

Explaination

After a thread is started, via its start() method of the Thread class, the JVM invokes the thread's run() method when the thread is initially executed.

Q 9 - Is it necessary that each try block must be followed by a catch block?

A - True.

B - False.

Answer : B

Explaination

It is not necessary that each try block must be followed by a catch block. It should be followed by either a catch block or a finally block.

Q 10 - Which of the following is a thread safe?

A - StringBuilder

B - StringBuffer

C - Both of the above

D - none of the above

Answer : B

Explaination

StringBuffer is thread safe.

java_questions_answers.htm