What are the Data Types supported by Java ? What is Autoboxing and Unbox- ing ?

3 years ago

OOP Java

The eight primitive data types supported by the Java programming language are:

byte
short
int
long
float
double
boolean
char

Autoboxing is the automatic conversion made by the Java compiler between the primitive types and their corresponding object wrapper classes. For example, the compiler converts an int to an Integer, a double to a Double, and so on. If the conversion goes the other way, this operation is called unboxing.

0

Surya Bikram Bhandari

Surya Bikram Bhandari

Oct 31, 2021

More related questions

1. Program to Reading and Writing a File in Java

2. WAP to print Right Triangle Pattern in Java

3. WAP to typecast the following: Double to String

4. WAP to typecast the following: String to Double

5. WAP to typecast the following: Double to Integer

6. WAP to typecast the following: Integer to Double

7. WAP to typecast the following: String to Integer

8. WAP to typecast the following: Integer to String

9. Write a program to show the use of auto-increment and auto-decrement operators.

10. Write a program to show the use of switch case statement.

11. WAP to show the use of ternary operator.

12. WAP to print prime numbers from 1 to 100.

13. WAP to check whether a number is prime or not.

14. WAP to print following Fibonacci series. 1, 1, 2, 3, 5, 8, …….. upto 15 terms.

15. WAP to find factorial of a number.

16. WAP to find sum of odd numbers from 1 to 100.

17. WAP to print first 15 even numbers.

18. WAP to print a series 1, 4, 9, 16, ….. upto 20 terms.

19. WAP to print a series. 5, 10, 15, 20, …… 50

20. WAP to find sum of numbers from 5 to 100.

21. WAP to find print numbers from 1 to 10.

22. WAP to input CP and SP and check profit or loss using scanner.

23. WAP to check whether a number a number is divisible by 7 but not by 13 using scanner.

24. WAP to check whether a number is exactly divisible by 5 and 10 using scanner.

25. WAP to check whether a number is divisible by 7 or not using scanner.

26. WAP to find area of circle using scanner.

27. WAP to check whether a number is odd or even using scanner.

28. WAP to find smallest among three numbers using scanner.

29. WAP to find largest among three numbers using scanner.

30. WAP to find smallest among two numbers using scanner.

31. WAP to find largest among two numbers using scanner.

32. WAP to find area of rectangle using scanner.

33. WAP to find simple interest using scanner.

34. WAP to add,subtract,multiply and divide two numbers using scanner.

35. WAP to find product of two number using scanner.

36. WAP to find a sum of two numbers using scanner.

37. WAP to input CP and SP and check profit or loss. Also find profit or loss amount.

38. WAP to check whether a number is divisible by 7 but not by 13.

39. WAP to check whether a number is exactly by 5 and 10.

40. WAP to check whether a number is divisible by 7 or not.

41. WAP to check whether a number is odd or even.

42. WAP to find smallest among three numbers.

43. WAP to find largest among three numbers.

44. WAP to find smallest among two numbers.

45. WAP to find largest among two numbers.

46. WAP to find area of circle.

47. WAP to add,subtract,multiply and divide two numbers.

48. WAP to find area of rectangle.

49. WAP to find simple interest.

50. WAP to find product of two number.

51. WAP to find sum of two numbers.

52. WAP to check whether a number is exactly by 5 and 10.

53. WAP to check whether a number is divisible by 7 or not.

54. WAP to check whether a number is odd or even.

55. WAP to find smallest among three numbers.

56. WAP to find largest among three numbers.

57. WAP to find smallest among two numbers.

58. WAP to find largest among two numbers.

59. WAP to find area of circle.

60. WAP to add,subtract,multiply and divide two numbers.

61. WAP to find area of rectangle.

62. WAP to find simple interest.

63. WAP to find product of two number.

64. WAP to find sum of two numbers.

65. OOP in Java 2020 - BCA(TU) Old Questions

66. OOP in Java 2019 - BCA(TU) Old Questions

67. WAP to print the table of a number using thread synchronization

68. WAP to count the no. of times high and low priority threads loop run (extending thread class)

69. WAP to count the no. of times high and low priority threads loop run (implementing runnable interface)

70. WAP to create multiple threads (extending thread class)

71. WAP to create multiple threads (implementing runnable interface)

72. WAP for setting priority of main thread

73. WAP to implement the concept of Abstract classes

74. WAP to implement bank account transactions using packages

75. WAP to implement bank account transactions

76. WAP to implement Multi-level inheritance

77. WAP to implement addition of 2 numbers using command Line (using parseInt() method)

78. Write a program to implement Rhombus pattern reading the limit form user

79. In loading programs into memory, what is the difference between load- time dynamic linking and run-time dynamic linking?

80. Write a program to implement keyboard events.

81. Write a program to implement mouse events.

82. Write a program to implement thread, applets and graphics by implementing animation of ball moving.

83. Write a program to calculate bonus for different departments using method overriding.

84. Write a program to create student report using applet, read the input using text boxes and display the o/p using buttons.

85. Write a program to create student report using applet, read the input using text boxes and display the o/p using buttons.

86. Write a program to implement constructor overloading by passing different number of parameter of different types.

87. Write a program to find area of geometrical figures using method.

88. Write a program to implement all string operations.

89. Write a program to sort list of elements in ascending and descending order and show the exception handling.

90. Write a program to display all prime numbers between two limits.

91. Write a program to find factorial of list of number reading input as command line argument.

92. What is meant by implicit objects and what are they ?

93. What are Expressions ?

94. What are Decalarations ?

95. What are Scriptlets ?

96. What are JSP actions ?

97. What are Directives ? What are the different types of Directives available in JSP ?

98. What are the advantages of JSP ?

99. What are the advantages of JSP ?

100. How are the JSP requests handled ?

101. What is a JSP Page ?

102. What is URL Encoding and URL Decoding ?

103. What’s the difference between sendRedirect and forward methods ?

104. What is HTTP Tunneling ?

105. Which protocol will be used by browser and servlet to communicate ?

106. What is a cookie ? What is the difference between session and cookie ?

107. What is the structure of the HTTP response ?

108. How do you find out what client machine is making a request to your servlet ?

109. What is Servlet Chaining ?

110. What is a Server Side Include (SSI) ?

111. What is meant by a Web Application ?

112. What is the difference between doGet() and doPost() ?

113. Explain the life cycle of a Servlet.

114. What is the difference between GenericServlet and HttpServlet ?

115. What is the difference between an Applet and a Servlet ?

116. Explain the architechure of a Servlet.

117. What is a Servlet ?

118. Explain Serialization and Deserialization.

119. Explain Marshalling and demarshalling.

120. What is the purpose of using RMISecurityManager in RMI ?

121. What is DGC ? And how does it work ?

122. What is the role of stub in RMI ?

123. What are the steps involved to make work a RMI program ?

124. What is the difference between using bind() and rebind() methods of Naming Class ?

125. What is meant by binding in RMI ?

126. What is the role of the java.rmi.Naming Class ?

127. What is the role of Remote Interface in RMI ?

128. What are the layers of RMI Architecture ?

129. What is the basic principle of RMI architecture ?

130. What is RMI ?

131. What does Connection pooling mean ?

132. What is the use of CallableStatement ? Name the method, which is used to prepare a CallableStatement.

133. What is the advantage of PreparedStatement over Statement ?

134. What is the purpose Class.forName method ?

135. Explain the role of Driver in JDBC

136. What is JDBC ?

137. What is the design pattern that Java uses for all Swing components ?

138. What advantage do Java’s layout managers provide over traditional window- ing systems ?

139. How can a GUI component handle its own events ?

140. What is the relationship between an event-listener interface and an event- adapter class ?

141. What is the relationship between clipping and repainting ?

142. What is the difference between a Window and a Frame ?

143. How are the elements of a GridBagLayout organized ?

144. How are the elements of a BorderLayout organized ?

145. What is the difference between a MenuItem and a CheckboxMenuItem ?

146. What is clipping ?

147. Name three Component subclasses that support painting.

148. Which Swing methods are thread-safe ?

149. What is the difference between a Scrollbar and a JScrollPane ?

150. What is a layout manager ?

151. What is the difference between a Choice and a List?

152. What is the applet security manager, and what does it provide ?

153. What is the applet class loader, and what does it provide ?

154. What is the difference between applets loaded over the internet and applets loaded via the file system ?

155. What are untrusted applets ?

156. What are the restrictions imposed on Java applets ?

157. What is the difference between an Applet and a Java Application ?

158. What happens when an applet is loaded ?

159. Explain the life cycle of an Applet.

160. What is an Applet ?

161. How does finally block differ from finalize() method ?

162. What will happen to the Exception object after exception handling ?

163. What is the importance of finally block in exception handling ?

164. What is the difference between throw and throws ?

165. What is the difference between Exception and Error in java ?

166. What are the two types of Exceptions in Java ? Which are the differences between them ?

167. Does Garbage collection occur in permanent generation space in JVM ?

168. When does an Object becomes eligible for Garbage collection in Java?

169. What is the difference between Serial and Throughput Garbage collector ?

170. What is structure of Java Heap ? What is Perm Gen space in Heap ?

171. If an object reference is set to null, will the Garbage Collector immediately free the memory held by that object ?

172. When is the finalize() called ? What is the purpose of finalization ?

173. What does System.gc() and Runtime.gc() methods do ?

174. What is the purpose of garbage collection in Java, and when is it used ?

175. What is the difference between HashSet and TreeSet ?

176. What’s the difference between Enumeration and Iterator interfaces ?

177. What are some of the best practices relating to the Java Collection framework ?

178. What is the tradeoff between using an unordered array versus an ordered array ?

179. What do you know about the big-O notation and can you give some examples with respect to different data structures ?

180. What is Java Priority Queue ?

181. What is Comparable and Comparator interface ? List their differences.

182. What is difference between ArrayList and LinkedList ?

183. What is difference between Array and ArrayList ? When will you use Array over ArrayList ?

184. What differences exist between HashMap and Hashtable ?

185. What is the importance of hashCode() and equals() methods ?

186. How HashMap works in Java ?

187. What is difference between fail-fast and fail-safe ?

188. What differences exist between Iterator and ListIterator ?

189. What is an Iterator ?

190. Why Collection doesn’t extend Cloneable and Serializable interfaces ?

191. What are the basic interfaces of Java Collections Framework ?

192. How do you ensure that N threads can access N resources without deadlock ?

193. What’s a deadlock ?

194. How does thread synchronization occurs inside a monitor ? What levels of synchronization can you apply ?

195. What is the difference between a synchronized method and a synchronized block ?

196. Explain the available thread states in a high-level.

197. Explain different ways of creating a thread. Which one would you prefer and why ?

198. What is the difference between processes and threads ?

199. What are pass by reference and pass by value ?

200. What is the difference between an Interface and an Abstract class ?

201. Does Java support multiple inheritance ?

202. What is a Constructor, Constructor Overloading in Java and Copy-Constructor

203. What is Function Overriding and Overloading in Java ?

204. Can you access non static variable in static context ?

205. What does the “static” keyword mean ? Can you override private or static method in Java ?

206. What is the Difference between JDK and JRE ?

207. What is JVM ? Why is Java called the Platform Independent Programming Lan- guage?

208. What is Object Oriented Programming (OOP)?

Questions Bank

View all Questions