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Java Interview Questions and Answers

Java Interview Questions and Answers
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Java Interview Questions and Answers

Java Interview Questions and Answers for beginners and experts. List of frequently asked Java Interview Questions with answers by Besant Technologies. We hope these Java interview questions and answers are useful and will help you to get the best job in the networking industry. This Java interview questions and answers are prepared by Java Professionals based on MNC Companies expectation. Stay tuned we will update New Java Interview questions with Answers Frequently. If you want to learn Practical Java Training then please go through this Java Training in Chennai and Java Training in Bangalore

Best Java Interview Questions and Answers

Besant Technologies supports the students by providing Java interview questions and answers for the job placements and job purposes. Java is the leading important course in the present situation because more job openings and the high salary pay for this Java and more related jobs. We provide the Java online training also for all students around the world through the Gangboard medium. These are top Java interview questions and answers, prepared by our institute experienced trainers.

Java interview questions and answers for the job placements

Here is the list of most frequently asked Java Interview Questions and Answers in technical interviews. These questions and answers are suitable for both freshers and experienced professionals at any level. The questions are for intermediate to somewhat advanced Java professionals, but even if you are just a beginner or fresher you should be able to understand the answers and explanations here we give.

Java interview questions and answers for Freshers and Experienced 

Here I am providing some of the important core java interview questions with answers that you should know. You can bookmark this post to brush up your knowledge before heading for an interview. Whether you are a fresher or highly experienced professional, java plays a vital role in any Java/JEE interview. Java is the favorite area in most of the interviews and plays a crucial role in deciding the outcome of your interview. This post is about java interview questions that come directly from 10+ years experienced Professionals of Java programming and lots of interviewing experience.

As a Java professional, it is essential to know the right buzzwords, learn the right technologies and prepare the right answers to commonly asked Java Interview Questions. Here’s a definitive list of top Java Interview Questions that will guarantee a breeze-through to the next level.

Q1) Why is Java known as the Platform Independent Programming Language?

Q2) Name the Data Types that are supported by Java?

Q3) Throw some light on the main features of Java.

Q4) Define Autoboxing and Unboxing?

Q5) What is Overloading and Overriding in Java?

Q6) How do you differentiate a HashSet class and a TreeSet class?

Q7) What is a List? What is the difference between an ArrayList and a LinkedList?

Q8) Define JVM, JDK and JRE?

Q9) Define the Java’s WORA nature?

Q10) How do you differentiate between StringBuffer & StringBuilder?

Q11) What is the case when you override hashcode() and equals() ? What problem can occur if we don’t override hashcode() method?

Q12) What are immutable classes?

Q13) Mention the access specifiers used in Java?

Q14) What is Singleton in Java?

Q15) Will all the Try blocks in Java end with Catch Blocks?

Q16) What is the Final Keyword in Java?

Q17) Is it possible to declare a class as Abstract without using any abstract method?

Q18) Any five differences between an Abstract Class and Interface in Java?

Q19) Define Serialization? When should we make use of serialization?

Q20) Explain multi-threading and the ways of implementing multi-threading in Java?

Q21) What is Collection and a Collections Framework?

Q22) What do you mean by BlockingQueue in Java Collections Framework?

Q23) What is the difference between ArrayList and Vector?

Q24) Define Constructor and Constructor Overloading in Java.

Q25) What are the differences between Enumeration and Iterator?

Q26) Why break is used in Switch Statement’s each case?

Q27) Name the different states of a thread.

Q28) Is it true that a java program never goes out of memory because of garbage collection feature?

Q29) How can you define Object Cloning in Java?

Q30) Is throw and throws keyword can be used interchangeably? If no, what is the difference between the two?

Q31.What is the difference between JDK, JRE, and JVM?

Q32. What is the difference between an Inner Class and a Sub-Class?

Q33. What is Final Keyword in Java? Give an example.

Q34. What’s the base class in Java from which all classes are derived?

Q36. What is a platform?

Q37. What is classloader?

Q38. What is the static method?

Q39.Can a class have multiple constructors?

Q40.What’s the difference between an array and Vector?

Q41. What are the two ways of implementing multi-threading in Java?

Q42. How can we execute any code even before the main method?

Q43.What’s the benefit of using inheritance a key?

Q44. What’s the difference between Stack and Queue?

Q45. Which types of exceptions are caught at compile time?

Q46. Is String a data type in java?

Q47. List any five features of Java?

Q49. What’s the difference between an array and Vector?

Q50. Why Java is considered dynamic?

Q51. Define class?

Q52. How would you call wait() method? Would you use if block or loop, and why?

Q53. How do you take thread dump in Java?

Q54.What is the difference between sleep and wait in Java?

Q55. Is ++ operator thread-safe in Java?

Q56. What is constructor chaining in Java?

Q57. Explain Java Heap Space and Garbage collection.

Q58. What is the difference between final, finalize and finally?

Q59. What is the difference between poll() and remove() method?

Q60. What kind of variables can a class consist of?

Q61. What is Singleton class?

Q62. List the three steps for creating an Object for a class?

Q63. When a byte datatype is used?

Q64. What do you mean by Access Modifier?

Q65. When parseInt() method can be used?

Q66. Why is StringBuffer called mutable?

Q67. What is an Exception?

Q68. When throw keyword is used?

Q69. When a super keyword is used?

Q70. Why Runnable Interface is used in Java?

Q71. What’s the purpose of using Break in each case of Switch Statement?

Q72. How we can execute any code even before main method?

Q73. Can we have two methods in a class with the same name?

Q74. How can we make the copy of a Java object?

Q75. Which types of exceptions are caught at compile time?

Q76. Can we use a default constructor of a class even if an explicit constructor is defined?

Q77. Can we override a method by using same method name and arguments but different return types?

Q78. What is an applet?

Q79. What is Comparable Interface?

Q80. Why IS Java application platform independent?

Q81. What are the actions present in the JVM?

Q82. What is the current version of JDK?

Q83. Java is fully OOPS language or not?

Q84. What is Wrapper class?

Q85. What is an Immutable class?

Q86. What is Array?

Q87. What is String?Difference between StringBuilder and StrinngBuffer?

Q88. What is Function?

Q89. What is Class?

Q90. What is Object?

Q91. What is Polymorphism?

Q92. What is Function Overloading?

Q93. What is Function Overriding?

Q94.Why used super and this keyword in java?

Q95. What is inheritance?

Q96.Describe the types of Inheritance?

Q97.What is scope?Describe the types of scope?

Q98.Types of Access Specifiers?

Q99.What is Encapsulation?

Q100.What is Abstraction?

Q101.What is Multitasking? How to achieve multitasking?

Q102.What is Thread?

Q103.what is Multithreading?

Q104.Difference between Multithreading and Multiprocessing?

Q105.What is Interface?

Q106.Difference between Interface and Abstraction?

Q107.What is Serialization?

Q108.What is DeSerialization?

Q109.What is Exception?types of Exception?

Q110.Explain Exception Handling methods?

Q111. What is Java ?

Q112. Which thread will execute first?

Q113. How to achieve lock?

Q114. How to get the current thread?

Q115. Difference between Array and Arraylist?

Q116. How to sort the collections?

Q117. Which data structure set uses?

Q118. Is wrapper classes overrides hashcode and equals method.

Q119. What is Treeset?

Q120. In which scenarios Arraylist and LinkedList will be used?

Q121. What happens if you add same key in the hashmap?

Q122. Can we add null key to the hashmap?

Q123. Hashmap put() operations uses which datastrcture when the hashcode is same ?

Q124. Does java 8 supports functional programming?

Q125. What is default method in java 8 interface?

Q126. Difference between stringbuffer and stringbuilder?

Q127. What is token in c

Q128. What is keywords, data type, constant and variable

Q129. What are the fundamental data type in c

Q130. What are the conditional statement

Q131. What are the un-conditional statement

Q132. What is if—else statement

Q133. What is switch case statements

Q134. What is conditional operator

Q135. What are the iterative statement

Q136. What is an array

Q137. What is sorting

Q138. What is searching

Q139. What is function

Q140. Explain the type of user define function

Q141. What is recursive function

Q142. What is structure

Q143. What is difference between structure and union

Q144. What is pre-processor directive

Q145. What is micro in c

Q146. What is file

Q147. What is file pointer

Q148. What is data structure

Q149. What is stack

Q150. What is queue

Q151. What is link list

Q152. What is binary tree

Q153. What is spanning tree

Q154. What is oops

Q155. What is polymorphism

Q156. What is abstraction

Q157. What is inheritance

Q158. What are type of inheritance in c++

Q159. What is constructor and destructor in c++

Q160. What is static keyword

Q162. What is pure virtual function

Q163. What is copy contractor in c++

Q164. What is Java

Q165. What final in java

Q166. What is super keyword in java

Q167. What the difference between abstract and interface

Q168. What is an applet program

Q169. What is swing

Q170. What is thread

Q171. What is synchronisation

Q172. What exceptional handling

Q173. What is JDBC

Q174. What are jdbc driver

Q175. What are steps involved in data base connectivity

Q176. What is servlet

Q177. What is life cycle of servlet

Q178. Write a servlet program

Q179. What is Jsp

Q180. What is difference between while and do-while

Q180. From which method the execution of java programs begins?

Q181. Which name will be checked by the compiler for the execution of program?

Q182. Which name will be checked by the JVM after the compiling the program?

Q183. Can we have filename and classname as same?

Q184 Define Expressions?

Q185. What will be the result of relational operators?

Q186. Which operators are used for masking the data in encryption and decryption process?

Q187. Which is maintained to manage the life cycle of local variables?

Q188. By how many ways the object can be created?

Q189. The object which has no reference is called?

Q190. In Heap memory which variables are created?

Q191. In java, how arrays are created?

Q192. Which operator is not used in java?

Q193. Define Runtime Polymorphism?

Q194. When null pointer exception occurs?

Q195. When Out of memory error occurs?

Q196. Can exceptions occur in catch block?

Q197. What will happen if we use throws keyword in body?

Q198. Which exceptions are used to represent the business/environmental failure?

Q199. In Java, Why multiple inheritance is not supported?

Q200. Which feature allows the JVM to run more than one thread in java?

Q201. Which methods are there in the thread class?

Q202. Can we have two start() methods in thread execution?

Q203. When Out of stack error occurs?

Q204. Where all string literals are managed?

Q205. Which condition will result in Illegal state exception?

Q206. Which will manage the lifecycle of thread?

Q207. What is the default priority of thread?

Q208. What is default priority of gc()?

Q209. Which interface will result in sorted order?

Q210. What is Comparator?

Q211. What is workspace?

Q212. Which will interact with hard disk?

Q213. What are Access specifiers?

Q214. Why we cannot be apply access specifiers to packages, initializers, local variables?

Q215. When we can use final class?

Q216. Abstract class cannot be instantiated. Why?

Q217. Abstract method cannot have body, why?

Java is being always the best and trending course for over 20 years. Our Java training in Chennai by Besant Technologies is ranked as best training institute by many people who got trained under this course. There are lots of job openings for Java developer and also there for many mobile applications development companies. In this blog, we are posting the best and top 100 Java interview questions and answers.

These Java interview questions and answers were prepared by the experienced and talented trainers and tutors from our institute and also by the Java developer those who are having 5+ years of experience.

Whether you are a fresher or highly experienced professional, java plays a vital role in any Java/JEE interview. Java is the favorite area in most of the interviews and plays a crucial role in deciding the outcome of your interview. This post is about java interview questions and answers.

As a Java professional, it is essential to know the right buzzwords, learn the right technologies and prepare the right answers to common Java Interview Questions and answers. Learn and study this Java interview questions and answers, move your carrier to the next level.

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