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 of the following is the default value of an instance variable?

A - null

B - 0

C - Depends upon the type of variable

D - Not assigned

Answer : C

Explaination

Instance variables are assigned default values based on their types. For example, int variable is assigned 0 and an object type variable is assigned null as default value.

Q 2 - Can we have two public classes in one java file?

A - True

B - False

Answer : B

Explaination

No, a java file can contain only one public class.

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

Answer : A

Explaination

char variable has default value of '\u0000' if defined as an instance/static variable.

Q 4 - Which of the following stands true about default modifier of class members?

A - By default, variables, methods and constructors can be accessed by subclass only.

B - By default, variables, methods and constructors can be accessed by any class lying in any package.

C - By default, variables, methods and constructors can be accessed by any class lying in the same package.

D - None of the above.

Answer : C

Explaination

By default, variables, methods and constructors can be accessed by any class lying in the same package.

Q 5 - What is Abstraction?

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

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

C - It refers to the ability to make a class abstract in OOP.

D - None of the above.

Answer : C

Explaination

It refers to the ability to make a class abstract in OOP. It helps to reduce the complexity and also improves the maintainability of the system.

Q 6 - What is an applet?

A - An applet is a Java program that runs in a Web browser.

B - Applet is a standalone java program.

C - Applet is a tool.

D - Applet is a run time environment.

Answer : A

Explaination

An applet is a Java program that runs in a Web browser.

Q 7 - Method Overloading is an example of

A - Static Binding.

B - Dynamic Binding.

C - Both of the above.

D - None of the above.

Answer : A

Explaination

Method Overloading is example of static binding.

Q 8 - What is synchronization?

A - Synchronization is the capability to control the access of multiple threads to shared resources.

B - Synchronization is the process of writing the state of an object to another object.

C - Synchronization is the process of writing the state of an object to byte stream.

D - None of the above.

Answer : A

Explaination

Synchronization is the capability to control the access of multiple threads to shared resources. synchronized keyword in java provides locking which ensures mutual exclusive access of shared resource and prevent data race.

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

A - True.

B - False.

Answer : B

Explaination

It is not necessary that each try block must be followed by a finally 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