Latest java Interview Questions and Answers 2024 for Freshers and Experienced

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If you're looking for current Java interview questions and answers, you've come to the right place! This Latest 2024 Question List will provide you with a comprehensive list of trending Java interview questions and answers asked in Top Companies interview round.

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#	Question	Options	Answer
101	In order to restrict a variable of a class from inheriting to subclass, how variable should be declared?	Protected Public Static Private	Private
102	All classes in Java are inherited from which class?	java.class.object java.lang.class java.lang.Object java.class.inherited	java.lang.Object
103	Using which of the following, multiple inheritance in Java can be implemented?	Multithreading Private methods Interfaces Protected methods	Interfaces
104	Which of this keyword must be used to inherit a class?	extends extent this super	extends
105	Which of these is supported by method overriding in Java?	class Polymorphism Encapsulation Abstraction	Polymorphism
106	If a class inheriting an abstract class does not define all of its function then it will be known as?	A simple class interface Abstract Static class	Abstract
107	Which of these is not abstract?	Queue List AbstractList Thread	Thread
108	Which of this package is used for handling security related issues in a program?	java.lang.security java.awt.image java.security java.io.security	java.security
109	Which of these methods can randomize all elements in a list?	randomize() rand() ambiguous() shuffle()	shuffle()
110	Which of these must contain a unique element?	List Set Collection Array	Set
111	Which of these interface handle sequences?	Collection Comparator List Set	List
112	Which of these is a method of ListIterator used to obtain index of previous element?	back() previous() goBack() previousIndex()	previousIndex()
113	Which of these methods can be used to move to next element in a collection?	hasNext() shuffle() move() next()	next()
114	Which of these return type of hasNext() method of an iterator?	Boolean Double Integer Collections Object	Boolean
115	What is Collection in Java?	A group of classes A group of interfaces A group of objects All of above	A group of objects
116	Which of these methods deletes all the elements from invoking collection?	refresh() delete() reset() clear()	clear()
117	Which of these classes is not part of Java’s collection framework?	Stack Queue Array Maps	Maps
118	Which of these packages contain all the collection classes?	java.net java.lang java.util java.awt	java.util
119	Which of these methods is used to retrieve the elements in properties object at specific location?	ElementAt() get() getProperty() Elementat()	getProperty()
120	Which of these method is used to insert value and its key?	addElement() insertElement() put() set()	put()
121	Which of these class object uses the key to store value?	Hashtable Dictionary Map All of above	All of above
122	Which of these methods is used to add elements in vector at specific location?	set() add() addElement() AddElement()	addElement()
123	Which of these are legacy classes?	Vector Stack Hashtable All of Above	All of Above
124	Which of these methods can be used to obtain set of all keys in a map?	keyall() keySet() getAll() getKeys()	keySet()
125	Which of these method is used to remove all keys/values pair from the invoking map?	removeAll() clear() remove() delete()	remove()
126	Which of the following is not OOPS concept in Java?	Inheritance Encapsulation Polymorphism Compilation	Compilation
127	Which of the following is a type of polymorphism in Java?	Compile time polymorphism Execution time polymorphism Multiple polymorphism Multilevel polymorphism	Compile time polymorphism
128	When does method overloading is determined?	At run time At compile time At coding time At execution time	At compile time
129	When Overloading does not occur?	More than one method with same name but different method signature and different number or type of parameters More than one method with same name, same signature but different number of signature More than one method with same name, same signature, same number of parameters but different type More than one method with same name, same number of parameters and type but different signature	More than one method with same name, same number of parameters and type but different signature
130	Which concept of Java is a way of converting real world objects in terms of class?	Polymorphism Encapsulation Abstraction Inheritance	Abstraction
131	Which concept of Java is achieved by combining methods and attribute into a class?	Encapsulation Inheritance Polymorphism Abstraction	Encapsulation
132	What is it called if an object has its own lifecycle and there is no owner?	Aggregation Composition Encapsulation Association	Association
133	What is it called where child object gets killed if parent object is killed?	Aggregation Composition Encapsulation Association	Composition
134	What is it called where object has its own lifecycle and child object cannot belong to another parent object?	Aggregation Composition Encapsulation Association	Aggregation
135	Method overriding is combination of inheritance and polymorphism?	True False None All of the above	True
136	What is the stored in the object obj in following lines of Java code? -> box obj;	Memory address of allocated memory of object NULL Any arbitrary pointer Garbage	NULL
137	Which of these keywords is used to make a class?	class struct int none of the mentioned	class
138	Which of the following is a valid declaration of an object of class Box?	Box obj = new Box(); Box obj = new Box; obj = new Box(); new Box obj;	Box obj = new Box();
139	Which of these statement is incorrect?	Every class must contain a main() method Applets do not require a main() method at all There can be only one main() method in a program main() method must be made public	Every class must contain a main() method
140	Which of the following statements is correct?	Public method is accessible to all other classes in the hierarchy Public method is accessible only to subclasses of its parent class Public method can only be called by object of its class Public method can be accessed by calling object of the public class	Public method is accessible to all other classes in the hierarchy
141	What is the return type of a method that does not return any value?	int float void double	void
142	Which of the following is a method having same name as that of it’s class?	finalize delete class constructor	constructor
143	Which method can be defined only once in a program?	main method finalize method static method private method	main method
144	Which of this statement is incorrect?	All object of a class are allotted memory for the all the variables defined in the class If a function is defined public it can be accessed by object of other class by inheritance main() method must be made public All object of a class are allotted memory for the methods defined in the class	All object of a class are allotted memory for the methods defined in the class
145	What is the return type of Constructors?	int float void none of the mentioned	none of the mentioned
146	Which keyword is used by the method to refer to the object that invoked it?	import catch abstract this	this
147	Which operator is used by Java run time implementations to free the memory of an object when it is no longer needed?	delete free new none of the mentioned	none of the mentioned
148	Which function is used to perform some action when the object is to be destroyed?	finalize() delete() main() none of the mentioned	finalize()
149	Which of the following statements are incorrect?	default constructor is called at the time of object declaration constructor can be parameterized finalize() method is called when a object goes out of scope and is no longer needed finalize() method must be declared protected	finalize() method is called when a object goes out of scope and is no longer needed
150	What is true about private constructor?	Private constructor ensures only one instance of a class exist at any point of time Private constructor ensures multiple instances of a class exist at any point of time Private constructor eases the instantiation of a class Private constructor allows creating objects in other classes	Private constructor ensures only one instance of a class exist at any point of time
151	What would be the behaviour if this() and super() used in a method?	Runtime error Throws exception compile time error Runs successfully	compile time error
152	What is false about constructor?	Constructors cannot be synchronized in Java Java does not provide default copy constructor Constructor can have a return type this and super can be used in a constructor	Constructor can have a return type
153	What is true about Class.getInstance()?	Class.getInstance calls the constructor Class.getInstance is same as new operator Class.getInstance needs to have matching constructor Class.getInstance creates object if class does not have any constructor	Class.getInstance creates object if class does not have any constructor
154	What is true about protected constructor?	Protected constructor can be called directly Protected constructor can only be called using super() Protected constructor can be used outside package protected constructor can be instantiated even if child is in a different package	Protected constructor can only be called using super()
155	What is not the use of this keyword in Java?	Passing itself to another method Calling another constructor in constructor chaining Referring to the instance variable when local variable has the same name Passing itself to method of the same class	Passing itself to method of the same class
156	What would be the behaviour if one parameterized constructor is explicitly defined?	Compilation error Compilation succeeds Runtime error Compilation succeeds but at the time of creating object using default constructor, it throws compilation error	Compilation succeeds but at the time of creating object using default constructor, it throws compilation error
157	What would be behaviour if the constructor has a return type?	Compilation error Runtime error Compilation and runs successfully Only String return type is allowed	Compilation error
158	What is the process of defining two or more methods within same class that have same name but different parameters declaration?	method overloading method overriding method hiding none of the mentioned	method overloading
159	Which of these can be overloaded?	Methods Constructors All of the mentioned None of the mentioned	All of the mentioned
160	Which of these is correct about passing an argument by call-by-value process?	Copy of argument is made into the formal parameter of the subroutine Reference to original argument is passed to formal parameter of the subroutine Copy of argument is made into the formal parameter of the subroutine and changes made on parameters of subroutine have effect on original argument Reference to original argument is passed to formal parameter of the subroutine and changes made on parameters of subroutine have effect on original argument	Copy of argument is made into the formal parameter of the subroutine
161	What is the process of defining a method in terms of itself, that is a method that calls itself?	Polymorphism Abstraction Encapsulation Recursion	Recursion
162	Which of these access specifiers must be used for main() method?	private public protected none of the mentioned	public
163	Which of these is used to access a member of class before object of that class is created?	public private static protected	static
164	Which of these is used as a default for a member of a class if no access specifier is used for it?	private public public, within its own package protected	private
165	What is the process by which we can control what parts of a program can access the members of a class?	Polymorphism Abstraction Encapsulation Recursion	Encapsulation
166	Which of the following statements are incorrect?	public members of class can be accessed by any code in the program private members of class can only be accessed by other members of the class private members of class can be inherited by a subclass, and become protected members in subclass protected members of a class can be inherited by a subclass, and become private members of the subclass	private members of class can be inherited by a subclass, and become protected members in subclass
167	Which of these access specifier must be used for class so that it can be inherited by another subclass?	public private protected none of the mentioned	public
168	Which one of the following is not an access modifier?	Public Private Protected Void	Void
169	All the variables of class should be ideally declared as?	private public protected default	private
170	Which of the following modifier means a particular variable cannot be accessed within the package?	private public protected default	private
171	How can a protected modifier be accessed?	accessible only within the class accessible only within package accessible within package and outside the package but through inheritance only accessible by all	accessible within package and outside the package but through inheritance only
172	What happens if constructor of class A is made private?	Any class can instantiate objects of class A Objects of class A can be instantiated only within the class where it is declared Inherited class can instantiate objects of class A classes within the same package as class A can instantiate objects of class A	Objects of class A can be instantiated only within the class where it is declared
173	All the variables of interface should be?	default and final default and static public, static and final protect, static and final	public, static and final
174	What is true of final class?	Final class cause compilation failure Final class cannot be instantiated Final class cause runtime failure Final class cannot be inherited	Final class cannot be inherited
175	How many copies of static and class variables are created when 10 objects are created of a class?	1, 10 10, 10 10, 1 1, 1	1, 10
176	Which is the modifier when there is none mentioned explicitly?	protected private public default	default
177	String in Java is a?	class object variable character array	class
178	Which of these method of String class is used to obtain character at specified index?	char() Charat() charat() charAt()	charAt()
179	Which of these keywords is used to refer to member of base class from a subclass?	upper super this none of the mentioned	super
180	Which of these method of String class can be used to test to strings for equality?	isequal() isequals() equal() equals()	equals()
181	Which of the following statements are incorrect?	String is a class Strings in java are mutable Every string is an object of class String Java defines a peer class of String, called StringBuffer, which allows string to be altered	Strings in java are mutable
182	Which of this keyword can be used in a subclass to call the constructor of superclass?	super this extent extends	super
183	What is the process of defining a method in a subclass having same name & type signature as a method in its superclass?	Method overloading Method overriding Method hiding None of the mentioned	Method overriding
184	Which of these keywords can be used to prevent Method overriding?	static constant protected final	final
185	Which of these is supported by method overriding in Java?	Abstraction Encapsulation Polymorphism None of the mentioned	Polymorphism
186	What is not type of inheritance?	Single inheritance Double inheritance Hierarchical inheritance Multiple inheritance	Double inheritance
187	Using which of the following, multiple inheritance in Java can be implemented?	Interfaces Multithreading Protected methods Private methods	Interfaces
188	All classes in Java are inherited from which class?	java.lang.class java.class.inherited java.class.object java.lang.Object	java.lang.Object
189	In order to restrict a variable of a class from inheriting to subclass, how variable should be declared?	Protected Private Public Static	Private
190	If super class and subclass have same variable name, which keyword should be used to use super class?	super this upper classname	super
191	Static members are not inherited to subclass.	True False Not Sure None	True
192	Which of the following is used for implementing inheritance through an interface?	inherited using extends implements	implements
193	Which of the following is used for implementing inheritance through class?	inherited using extends implements	extends
194	What would be the result if a class extends two interfaces and both have a method with same name and signature? Lets assume that the class is not implementing that method.	Runtime error Compile time error Code runs successfully First called method is executed successfully	Compile time error
195	Which of these class is superclass of every class in Java?	String class Object class Abstract class ArrayList class	Object class
196	Which of these method of Object class can clone an object?	Objectcopy() copy() Object clone() clone()	Object clone()
197	Which of these method of Object class is used to obtain class of an object at run time?	get() void getclass() Class getclass() None of the mentioned	Class getclass()
198	Which of these keywords can be used to prevent inheritance of a class?	super constant class final	final
199	Which of these keywords cannot be used for a class which has been declared final?	abstract extends abstract and extends none of the mentioned	abstract
200	Which of these class relies upon its subclasses for complete implementation of its methods?	Object class abstract class ArrayList class None of the mentioned	abstract class

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