610+ Java Programming Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Bachelor of Computer Applications (BCA) , Bachelor of Science in Computer Science (BSc CS) , Master of Computer Applications (MCA) , Programming Languages .

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151.	Which of the following will cause a semantic error, if you are trying to compare x to 5?
A.	if (x == 5)
B.	if (x = 5)
C.	if (x <= 5)
D.	if (x >= 5)
Answer» B. if (x = 5)

152.	How many constructors does the class Exception have?
A.	0
B.	1
C.	2
D.	3
Answer» C. 2

153.	If class Dog has a subclass Retriever, which of the following is true?
A.	Because of single inheritance, Dog can have no other subclasses.
B.	Because of single inheritance, Retriever can extend no other class except Dog.
C.	The relationship between these classes implies that Dog “is-a” Retriever.
D.	The relationship between these classes implies that Retriever “has-a” Dog.
Answer» B. Because of single inheritance, Retriever can extend no other class except Dog.

154.	If there are three classes: Shape, Circle, and Square, what is the most likely relationship between them?
A.	Square is a superclass, and Shape and Circle are subclasses of Square.
B.	Shape is a superclass, and Circle and Square are subclasses of Shape.
C.	Shape, Circle, and Square are all sibling classes.
D.	These three classes cannot be related.
Answer» B. Shape is a superclass, and Circle and Square are subclasses of Shape.

155.	What is byte code in the context of Java?
A.	The type of code generated by a Java compiler
B.	The type of code generated by a Java Virtual Machine
C.	It is another name for a Java source file
D.	It is the code written within the instance methods of a class.
Answer» A. The type of code generated by a Java compiler

156.	What is garbage collection in the context of Java?
A.	The operating system periodically deletes all of the java files available on the system.
B.	Any package imported in a program and not used is automatically deleted.
C.	When all references to an object are gone, the memory used by the object is automatically reclaim
Answer» C. When all references to an object are gone, the memory used by the object is automatically reclaim

157.	What is different between a Java applet and a Java application?
A.	An application can in general be trusted whereas an applet can't.
B.	An applet must be executed in a browser environment.
C.	An applet is not able to access the files of the computer it runs on
D.	All of the above
Answer» D. All of the above

158.	JAR stands for?
A.	Java Archive
B.	Java Archive Runner
C.	Java Application Runner
D.	None of the above
Answer» A. Java Archive

159.	What are the pillars of OOPS concept?
A.	Abstraction, Inheritance, Encapsulation, Polymorphism
B.	Atomicity, Inheritance, Encapsulation, Polymorphism
C.	Abstraction, Inheritance, Polymorphism
D.	None of the Above
Answer» A. Abstraction, Inheritance, Encapsulation, Polymorphism

160.	What is the default buffer size used by any buffered class?
A.	128 bytes
B.	256 bytes
C.	512 bytes
D.	1024 bytes
Answer» C. 512 bytes

161.	Which class cannot be a subclass in java
A.	Abstract class
B.	Parent class
C.	Final class
D.	None of above
Answer» C. Final class

162.	Why we use array as a parameter of main method
A.	It is syntax
B.	Can store multiple values
C.	Both of above
D.	None of above
Answer» B. Can store multiple values

163.	What is process of defining two or more methods within same class that have same name but different parameters declaration?
A.	Method overloading
B.	Method overriding
C.	Method hiding
D.	None of the mentioned
Answer» A. Method overloading

164.	Which of these can be overloaded?
A.	Methods
B.	Constructors
C.	Both a & b
D.	None of the mentioned
Answer» C. Both a & b

165.	Which of these is correct about passing an argument by call-by-value process?
A.	Copy of argument is made into the formal parameter of the subroutine.
B.	Reference to original argument is passed to formal parameter of the subroutine.
C.	Copy of argument is made into the formal parameter of the subroutine and changes made on parameters of subroutine have effect on original argument.
D.	Reference to original argument is passed to formal parameter of the subroutine and changes made on parameters of subroutine have effect on original argument.
Answer» A. Copy of argument is made into the formal parameter of the subroutine.

166.	What is the process of defining a method in terms of itself that is a method that calls itself?
A.	Polymorphism
B.	Abstraction
C.	Encapsulation
D.	Recursion
Answer» D. Recursion

167.	Which of the following statements are incorrect?
A.	Default constructor is called at the time of declaration of the object if a constructor has not been defined.
B.	Constructor can be parameterized.
C.	Finalize() method is called when a object goes out of scope and is no longer need
Answer» C. Finalize() method is called when a object goes out of scope and is no longer need

168.	What is the stored in the object obj in following lines of code? box obj;
A.	Memory address of allocated memory of object.
B.	NULL
C.	Any arbitrary pointer
D.	Garbage
Answer» B. NULL

169.	Which of the following is a valid declaration of an object of class Box?
A.	Box obj = new Box();
B.	Box obj = new Box;
C.	obj = new Box();
D.	new Box obj;
Answer» A. Box obj = new Box();

170.	Which of this statement is incorrect?
A.	Every class must contain a main() method.
B.	Applets do not require a main() method at all.
C.	There can be only one main() method in a program.
D.	main() method must be made public.
Answer» A. Every class must contain a main() method.

171.	Which of the following statements is correct?
A.	Public method is accessible to all other classes in the hierarchy
B.	Public method is accessible only to subclasses of its parent class
C.	Public method can only be called by object of its class.
D.	Public method can be accessed by calling object of the public class.
Answer» A. Public method is accessible to all other classes in the hierarchy

172.	Program which executes applet is known as
A.	applet engine
B.	virtual machine
C.	JVM
D.	None of above
Answer» A. applet engine

173.	You read the following statement in a Java program that compiles and executes. submarine.dive(depth); What can you say for sure?
A.	Depth must be an int
B.	Dive must be a method.
C.	Dive must be the name of an instance fie
Answer» B. Dive must be a method.

174.	Which is true about an anonymous inner class?
A.	It can extend exactly one class and implement exactly one interface.
B.	It can extend exactly one class and can implement multiple interfaces.
C.	It can implement multiple interfaces regardless of whether it also extends a class.
D.	none
Answer» B. It can extend exactly one class and can implement multiple interfaces.

175.	If a thread is to be declared as a daemon thread, it must be declared before
A.	start method
B.	run method
C.	stop method
D.	none
Answer» A. start method

610+ Java Programming Solved MCQs

Which of the following will cause a semantic error, if you are trying to compare x to 5?

How many constructors does the class Exception have?

If class Dog has a subclass Retriever, which of the following is true?

If there are three classes: Shape, Circle, and Square, what is the most likely relationship between them?

What is byte code in the context of Java?

What is garbage collection in the context of Java?

What is different between a Java applet and a Java application?

JAR stands for?

What are the pillars of OOPS concept?

What is the default buffer size used by any buffered class?

Which class cannot be a subclass in java

Why we use array as a parameter of main method

What is process of defining two or more methods within same class that have same name but different parameters declaration?

Which of these can be overloaded?

Which of these is correct about passing an argument by call-by-value process?

What is the process of defining a method in terms of itself that is a method that calls itself?

Which of the following statements are incorrect?

What is the stored in the object obj in following lines of code? box obj;

Which of the following is a valid declaration of an object of class Box?

Which of this statement is incorrect?

Which of the following statements is correct?

Program which executes applet is known as

You read the following statement in a Java program that compiles and executes. submarine.dive(depth); What can you say for sure?

Which is true about an anonymous inner class?

If a thread is to be declared as a daemon thread, it must be declared before

Under what circumstances might you use the yield method of the Thread class

Which of the following is the correct syntax for suggesting that the JVM performs garbage collection?

A class that cannot be a subclass is called as______ class.

When method defined in subclass which has same signature as a method in a super class, it is known as method

Which of the following statement is correct?

Java language has support for which of the following types of comment ?

Consider the following program: import myLibrary.*; public class ShowSomeClass { // code for the class... } What is the name of the java file containing this program?

Which of the following is TRUE?

Consider the following code snippet String river = new String(“Columbia”); System.out.println(river.length()); What is printed?

What is different between a Java applet and a Java application?

You read the following statement in a Java program that compiles and executes. submarine.dive(depth); What can you say for sure?

Consider public class MyClass{ public MyClass(){/*code*/} // more code... } To instantiate MyClass, you would write?

In Java Inheritance

What happens in a method if there is an exception thrown in a try block but there is no catch block following the try block?

The class RuntimeException is the superclass of which of the following classes?

How many finally blocks can there be in a try/catch structure?

Which of the following statements is NOT true about creating your own exceptions?

What can a method do with a checked exception?

Which of the following is an exception thrown by the methods of the class String?

Which of the following statements is true?

A message string is returned by which method of an Exception object?

When is a finally {} block executed?

When does Exceptions in Java arises in code sequence?

Which of these keywords is not a part of exception handling?

Which of these keywords is used to manually throw an exception?

Consider public class MyClass{ public MyClass(){/code/} // more code... } To instantiate MyClass, you would write?

176.	Under what circumstances might you use the yield method of the Thread class
A.	To call from the currently running thread to allow another thread of the same or higher priority to run
B.	To call on a waiting thread to allow it to run
C.	To allow a thread of higher priority to run
D.	To call from the currently running thread with a parameter designating which thread should be allowed to run
Answer» A. To call from the currently running thread to allow another thread of the same or higher priority to run

177.	Which of the following is the correct syntax for suggesting that the JVM performs garbage collection?
A.	System.free();
B.	System.setGarbageCollection();
C.	System.out.gc();
D.	System.gc();
Answer» D. System.gc();

178.	A class that cannot be a subclass is called as______ class.
A.	abstract
B.	parent class
C.	Final
D.	none of these
Answer» C. Final

179.	When method defined in subclass which has same signature as a method in a super class, it is known as method
A.	Overloading
B.	Overriding
C.	Packing
D.	None of these
Answer» B. Overriding

180.	Which of the following statement is correct?
A.	For positive numbers, result of operators >> and >>> are same
B.	Java provides two operators to do left shift <<< and <<
C.	>> is the zero fill right shift operator
D.	>>> is the signed right shift operator
Answer» A. For positive numbers, result of operators >> and >>> are same

181.	Java language has support for which of the following types of comment ?
A.	block, line and javadoc
B.	javadoc, literal and string
C.	javadoc, char and string
D.	single, multiple and quote
Answer» A. block, line and javadoc

182.	Consider the following program: import myLibrary.*; public class ShowSomeClass { // code for the class... } What is the name of the java file containing this program?
A.	myLibrary.java
B.	ShowSomeClass.java
C.	ShowSomeClass
D.	ShowSomeClass.class 1.
Answer» B. ShowSomeClass.java

183.	Which of the following is TRUE?
A.	In java, an instance field declared public generates a compilation error.
B.	int is the name of a class available in the package java.lang
C.	Instance variable names may only contain letters and digits.
D.	A class has always a constructor (possibly automatically supplied by the java compiler).
Answer» D. A class has always a constructor (possibly automatically supplied by the java compiler).

184.	Consider the following code snippet String river = new String(“Columbia”); System.out.println(river.length()); What is printed?
A.	6
B.	7
C.	8
D.	Columbia
Answer» C. 8

185.	What is different between a Java applet and a Java application?
A.	An application can in general be trusted whereas an applet can't.
B.	An applet must be executed in a browser environment.
C.	An applet is not able to access the files of the computer it runs on
D.	(A), (B) and (C).
Answer» D. (A), (B) and (C).