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 - Which of the following is not a keyword in java?

Answer : B

Explaination

Boolean is a class and is not a keyword.

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 double variable?

Answer : A

Explaination

double variable has default value of 0.0d 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 Overriding is an example of

A - Static Binding.

B - Dynamic Binding.

C - Both of the above.

D - None of the above.

Answer : B

Explaination

Method Overriding is example of dynamic Binding.

Q 8 - What is a transient variable?

A - A transient variable is a variable which is serialized during Serialization.

B - A transient variable is a variable that may not be serialized during Serialization.

C - A transient variable is a variable which is to be marked as serializable.

D - None of the above.

Answer : B

Explaination

A transient variable is a variable that may not be serialized during Serialization and which is initialized by its default value during de-serialization.

Q 9 - Deletion is faster in LinkedList than ArrayList.

A - True.

B - False.

Answer : A

Explaination

Deletion in linked list is fast because it involves only updating the next pointer in the node before the deleted node and updating the previous pointer in the node after the deleted node.

Q 10 - What is currentThread()?

A - It is a Thread public static method used to obtain a reference to the current thread.

B - It is a thread's instance method used to get thread count.

C - It is a object's public static method used obtain a reference to the current thread.

D - It is a object's instance method used to get thread count.

Answer : A

Explaination

currentThread() is a public static method of Thread class used to obtain a reference to the current thread.

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