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
1	Which of those doesn’t have an index based structure?	List Set Map Queue	Set
2	java.util.Collections is a:	Class Interface Object None of the above	Class
3	Methods such as reverse, shuffle are offered in:	Object Collection Collections Apache Commons Collections	Collections
4	Which of those allows duplicate elements?	Set List All None of the above	List
5	Which allows the storage of a null key and null values?	Hashtable HashMap Set None of the above	HashMap
6	Which interface should be implemented for sorting on basis of many criteria’s?	Comparator Comparable Serializable None of the above	Comparator
7	What guarantees type-safety in a collection?	Generics Abstract classes Interfaces Collection	Generics
8	The most used interfaces from the collection framework are?	List Map Set Queue	Map
9	The root interface of Java collection framework hierarchy is –	Collection Root Collections List/Set	List/Set
10	Which of those is synchronized?	ArrayList LinkedList Vector None of the above	Vector
11	ArrayList implements that of the following?	List RandomAccess Cloneable All of these	All of these
12	Which of those permits the storage of the many null values?	Set List None of these All of these	All of these
13	Which doesn’t permit to store a null value?	TreeSet LinkedHashSet HashSet None	TreeSet
14	TreeMap implements?	Dictionary HashMap AbstractMap Navigable Map	Navigable Map
15	Which of these standard collection classes implements a dynamic array?	LinkedList AbstractSet AbstractList ArrayList	ArrayList
16	Which of these method of ArrayList class is used to obtain present size of an object?	capacity() index() size() length()	size()
17	Which of the below does not implement Map interface?	HashMap Hashtable Vector EnumMap	Vector
18	How to externally synchronize hashmap?	HashMap.synchronize(HashMap a); Collections.synchronizedMap(new HashMap()); HashMap a = new HashMap(); Collections.synchronize(new HashMap());	Collections.synchronizedMap(new HashMap());
19	How can we remove an object from ArrayList?	remove() method and using Iterator delete() method using Iterator remove() method	remove() method and using Iterator
20	Which class provides thread safe implementation of List?	ArrayList List HashList CopyOnWriteArrayList	CopyOnWriteArrayList
21	What is the relation between hashset and hashmap?	HashMap is the interface; HashSet is the concrete class HashMap internally implements HashSet HashSet internally implements HashMap HashSet is the interface; HashMap is the concrete class	HashSet internally implements HashMap
22	Which of these object stores association between keys and values?	Map Array Hash table String	Map
23	Which of these classes provide implementation of map interface?	LinkedList ArrayList HashMap DynamicList	HashMap
24	Which of these methods can be used to obtain set of all keys in a map?	keyall() getAll() getKeys() keySet()	keySet()
25	Which of these are legacy classes?	Vector All of the mentioned Stack Hashtable	All of the mentioned
26	Which of the following is not OOPS concept in Java?	Inheritance Encapsulation Polymorphism Compilation	Compilation
27	When does method overloading is determined?	At run time At compile time At coding time At execution time	At compile time
28	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
29	Which concept of Java is a way of converting real world objects in terms of class?	Polymorphism Encapsulation Abstraction Inheritance	Abstraction
30	Which concept of Java is achieved by combining methods and attribute into a class?	Encapsulation Inheritance Polymorphism Abstraction	Encapsulation
31	What is it called where child object gets killed if parent object is killed?	Aggregation Composition Encapsulation Association	Composition
32	Which component is used to compile, debug and execute java program?	JVM JDK JIT JRE	JDK
33	Which component is responsible for converting bytecode into machine specific code?	JVM JDK JIT JRE	JVM
34	Which component is responsible to run java program?	JVM JDK JIT JRE	JRE
35	Which component is responsible to optimize bytecode to machine code?	JVM JDK JIT JRE	JIT
36	Which of the below is invalid identifier with the main method?	public static private final	private
37	What is use of interpreter?	They convert bytecode to machine language code They read high level code and execute them They are intermediated between JIT and JVM It is a synonym for JIT	They read high level code and execute them
38	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();
39	Which of these operators is used to allocate memory for an object?	malloc alloc new give	new
40	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
41	What is the process of defining more than one method in a class differentiated by method signature?	Method overriding Method overloading Method doubling None of the mentioned	Method overloading
42	Which of the following is a method having same name as that of it’s class?	finalize delete class constructor	constructor
43	Which method can be defined only once in a program?	main method finalize method static method private method	main method
44	Which keyword is used by the method to refer to the object that invoked it?	import catch abstract this	this
45	Which function is used to perform some action when the object is to be destroyed?	finalize() delete() main() none of the mentioned	finalize()
46	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
47	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
48	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
49	Which of these is used as default for a member of a class if no access specifier is used for it?	public public, within its own package protected private	private
50	What is use of interpreter?	They are intermediated between JIT and JVM It is a synonym for JIT They convert bytecode to machine language code They read high level code and execute them	They read high level code and execute them
51	What is the extension of compiled java classes?	.txt .class .js .java	.class
52	Which of the below is invalid identifier with main method?	private final static public	private
53	Which of these package is used for text formatting in Java programming language?	java.awt java.awt.text java.io java.text	java.text
54	Which environment variable is used to set java path?	CLASSPATH JAVA_HOME MAVEN_HOME JAVA	JAVA_HOME
55	Which of these can not be used for a variable name in Java?	identifier identifier & keyword keyword None of these	keyword
56	Literals in java must be appended by which of these?	L L and I D l	L and I
57	What is true of final class?	Final class cannot be instantiated Final class cannot be inherited Final class cause compilation failure Final class cause runtime failure	Final class cannot be inherited
58	All the variables of interface should be ?	default and static default and final protect, static and final public,static and final	public,static and final
59	How can a protected modifier be accessed?	accessible by all accessible only within package accessible only within the class accessible within package and outside the package but through inheritance only	accessible within package and outside the package but through inheritance only
60	Which of the following modifier means a particular variable cannot be accessed within the package?	protected default private public	private
61	All the variables of class should be ideally declared as ?	default private public protected	private
62	Which one of the following is not an access modifier?	Void Protected Private Public	Void
63	Which of the following is not a valid flow control statement?	continue break return exit()	exit()
64	What is true about do statement?	do statement executes the code more than once always do statement executes the code of a loop at least once do statement does not get execute if condition is not matched in the first iteration do statement checks the condition at the beginning of the loop	do statement executes the code of a loop at least once
65	Which of the following loops will execute the body of loop even when condition controlling the loop is initially false?	while for if do-while	do-while
66	Which of these method of class StringBuffer is used to find the length of current character sequence?	Length() capacity() Capacity() length()	length()
67	Which of these method of class String is used to remove leading and trailing whitespaces?	Trim() doTrim() startsWith() trim()	trim()
68	Which of this method of class String is used to extract a substring from a String object?	Substring() tostring() substring() SubString()	substring()
69	Which of these method of class String is used to compare two String objects for their equality?	Isequal() isequal() Equals() equals()	equals()
70	Which of these is an incorrect statement?	String objects are mutable, they cannot be changed StringBuffer class is used to store string in a buffer for later use String object can point to some other reference of String variable String objects are immutable, they cannot be changed	StringBuffer class is used to store string in a buffer for later use
71	Which of this method of class String is used to obtain a length of String object?	Sizeof() length() get() lengthof()	length()
72	Which of these methods can be used to search an element in a list?	get() binaryserach() sort() find()	binaryserach()
73	Which of these cannot be declared static?	variable method class object	object
74	Which of these keywords is used to prevent content of a variable from being modified?	last final constant static	final
75	Arrays in Java are implemented as?	object class variable method	object
76	Where is array stored in memory?	first generation memory stack space heap space and stack space heap space	heap space
77	Can you make an array volatile?	No Not possible True False	True
78	Which of these is an incorrect Statement?	Array can be initialized when they are declared. Array can be initialized using comma separated expressions surrounded by curly braces. It is necessary to use new operator to initialize an array. None of these	It is necessary to use new operator to initialize an array.
79	Which of these classes is super class of Exception class?	Class RunTime Throwable System	Throwable
80	Which of these methods return description of an exception?	obtainException() obtainDescription() getMessage() getException()	getMessage()
81	Which of these statements is incorrect?	try can be followed by both catch and finally block try need not to be followed by anything try block need not to be followed by catch block try block can be followed by finally block instead of catch block	try need not to be followed by anything
82	Which of these keywords are used for generating an exception manually?	check try catch throw	throw
83	Which of these keywords are used for the block to handle the exceptions generated by try block?	check throw try catch	catch
84	Which of these keywords are used for the block to be examined for exceptions?	try catch throw check	try
85	What is the use of try and catch?	It allows to fix errors It prevents automatic terminating of the program in cases when an exception occurs It allows us to manually handle the exception All of Above	All of Above
86	Which of these exceptions will occur if we try to access the index of an array beyond its length?	ArrayIndexException ArithmeticException ArrayIndexOutOfBoundsException ArrayException	ArrayIndexOutOfBoundsException
87	A single try block must be followed by which of these?	try finally catch finally & catch	finally & catch
88	Which of these clause will be executed even if no exceptions are found?	catch throw finally throws	finally
89	Which of these class is related to all the exceptions that are explicitly thrown?	Exception Throw Error Throwable	Throwable
90	Which of these keywords is used to generate an exception explicitly?	catch throw finally try	throw
91	What exception thrown by parseInt() method?	NullPointerException NumberFormatException ArithmeticException ClassNotFoundException	NumberFormatException
92	Which of these handles the exception when no catch is used?	throw handler Java run time system Default handler finally	Default handler
93	Which of these class is related to all the exceptions that cannot be caught?	Exception RuntimeExecption Error All of above	Error
94	Which part of code gets executed whether exception is caught or not?	throw try finally catch	finally
95	Which of the following keywords is used for throwing exception manually?	catch throw try finally	throw
96	What would be the result if a class extends two interfaces and both have a method with same name and signature?	Code runs successfully First called method is executed successfully Runtime error Compile time error	Compile time error
97	Which of the following is used for implementing inheritance through class?	implements inherited using extends	extends
98	Which of the following is used for implementing inheritance through an interface?	extends inherited implements using	implements
99	Static members are not inherited to subclass.	return 0 return values False True	False
100	If super class and subclass have same variable name, which keyword should be used to use super class?	this classname super upper	super

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Basic syntax and data types
Object-oriented programming concepts
Control structures, such as loops and conditions
Exception handling
Collections and generics
Multithreading and concurrency
Advanced topics such as functional programming and design patterns

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