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 - Objects are stored on Stack.

A - True

B - False

Answer : B

Explaination

Objects are allocated memory in heap memory space.

Q 2 - Can we have multiple classes in same java file?

A - True

B - False

Answer : A

Explaination

True, a java file can contain one public class and many other non-public classes.

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

Answer : B

Explaination

Short variable has default value of 0 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 class variable?

A - class variables are static variables within a class but outside any method.

B - class variables are variables defined inside methods, constructors or blocks.

C - class variables are variables within a class but outside any method.

D - None of the above.

Answer : A

Explaination

Class variables are variables declared with in a class, outside any method, with the static keyword.

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 - What is function overloading?

A - Methods with same name but different parameters.

B - Methods with same name but different return types.

C - Methods with same name, same parameter types but different parameter names.

D - None of the above.

Answer : A

Explaination

If a class has multiple functions by same name but different parameters, it is known as Method Overloading.

Q 8 - Which is the way in which a thread can enter the waiting state?

A - Invoke its sleep() method.

B - invoke object's wait method.

C - Invoke its suspend() method.

D - All of the above.

Answer : D

Explaination

A thread can enter the waiting state by invoking its sleep() method, by blocking on IO, by unsuccessfully attempting to acquire an object's lock, or by invoking an object's wait() method. It can also enter the waiting state by invoking its (deprecated) suspend() method.

Q 9 - Under what conditions is an object's finalize() method invoked by the garbage collector?

A - When it detects that the object has become unreachable.

B - As soon as object is set as null.

C - At fixed intervalm it checks for null value.

D - None of the above.

Answer : A

Explaination

The garbage collector invokes an object's finalize() method when it detects that the object has become unreachable.

Q 10 - Which method must be implemented by all threads?

Answer : D

Explaination

All threads must implement the run() method.

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