Frequently Asked Questions - Java & Advanced Java

1. Can a main() method of class be invoked in another class?
2. What is the difference between java command line arguments and C command  line arguments?
3. What is the difference between == & .equals
4. What is the difference between abstract class & Interface.
5. What is singleton class & it's implementation.
6. Use of static,final variable
7. Examples of final class
8. Difference between Event propagation & Event delegation
9. Difference between Unicast & Multicast model
10. What is a java bean
11. What is synchronized keyword used for.
12. What are the restrictions of an applet & how to make the applet access the local machines resources.
13. What is reflect package used for & the methods of it.
14. What is serialization used for
15. Can methods be overloaded based on the return types ?
16. Why do we need a finalze() method when Garbage Collection is there ?
17. Difference between AWT and Swing compenents ?
18. Is there any heavy weight component in Swings ?
19. Can the Swing application if you upload in net, be compatible with your browser?
20. What should you do get your browser compatible with swing  components?
21. What are the methods in Applet ?
22. When is init(),start() called ?
23. When you navigate from one applet to another what are the methods called?
24. What is the difference between Trusted and Untrusted Applet ?
25. What is Exception ?
26. What are the ways you can handle exception ?
27. When is try,catch block used ?
28. What is finally method in Exceptions ?
29. What are the types of access modifiers ?
30. What is protected and friendly ?
31. What are the other modifiers ?
32. Is synchronised modifier ?
33. What is meant by polymorphism ?
34. What is inheritance ?
35. What is method Overloading ? What is this in OOPS ?
36. What is method Overriding ? What is it in OOPS ?
37. Does java support multi dimensional arrays ?
38. Is multiple inheritance used in Java ?
39. How do you send a message to the browser in JavaScript ?
40. Does javascript support multidimensional arrays ?
41. Is there any tool in java that can create reports ?
42. What is meant by Java ?
43. What is meant by a class ?
44. What is meant by a method ?
45. What are the OOPS concepts in Java ?
46. What is meant by encapsulation ? Explain with an example
47. What is meant by inheritance ? Explain with an example
48. What is meant by polymorphism ? Explain with an example
49. Is multiple inheritance allowed in Java ? Why ?
50. What is meant by Java interpreter ?
51. What is meant by JVM ?
52. What is a compilation unit ?
53. What is meant by identifiers ?
54. What are the different types of modifiers ?
55. What are the access modifiers in Java ?
56. What are the primitive data types in Java ?
57. What is meant by a wrapper class ?
58. What is meant by static variable and static method ?
59. What is meant by Garbage collection ?
60. What is meant by abstract class
61. What is meant by final class, methods and variables ?
62. What is meant by interface ?
63. What is meant by a resource leak ?
64. What is the difference between interface and abstract class ?
65. What is the difference between public private, protected and static
66. What is meant by method overloading ?
67. What is meant by method overriding ?
68. What is singleton class ?
69. What is the difference between an array and a vector ?
70. What is meant by constructor ?
71. What is meant by casting ?
72. What is the difference between final, finally and finalize ?
73. What is meant by packages ?
74. What are all the packages ?
75. Name 2 calsses you have used ?
76. Name 2 classes that can store arbitrary number of objects ?
77. What is the difference between java.applet.* and java.applet.Applet ?
78. What is a default package ?
79. What is meant by a super class and how can you call a super class ?
80. What is anonymous class ?
81. Name interfaces without a method ?
82. What is the use of an interface ?
83. What is a serializable interface ?
84. How to prevent field from serialization ?
85. What is meant by exception ?
86. How can you avoid the runtime exception ?
87. What is the difference between throw and throws ?
88. What is the use of finally ?
89. Can multiple catch statements be used in exceptions ?
90. Is it possible to write a try within a try statement ?
91. What is the method to find if the object exited or not ?
92. What is meant by a Thread ?
93. What is meant by multi-threading ?
94. What is the 2 way of creating a thread ? Which is the best way and why?
95. What is the method to find if a thread is active or not ?
96. What are the thread-to-thread communcation ?
97. What is the difference between sleep and suspend ?
98. Can thread become a member of another thread ?
99. What is meant by deadlock ?
100. How can you avoid a deadlock ?
101. What are the three typs of priority ?
102. What is the use of synchronizations ?
103. Garbage collector thread belongs to which priority ?
104. What is meant by time-slicing ?
105. What is the use of 'this' ?
106. How can you find the length and capacity of a string buffer ?
107. How to compare two strings ?
108. What are the interfaces defined by Java.lang ?
109. What is the purpose of run-time class and system class
110. What is meant by Stream and Types ?
111. What is the method used to clear the buffer ?
112. What is meant by Stream Tokenizer ?
113. What is serialization and de-serialisation ?
114. What is meant by Applet ?
115. How to find the host from which the Applet has originated ?
116. What is the life cycle of an Applet ?
117. How do you load an HTML page from an Applet ?
118. What is meant by Applet Stub Interface ?
119. What is meant by getCodeBase and getDocumentBase method ?
120. How can you call an applet from a HTML file
121. What is meant by Applet Flickering ?
122. What is the use of parameter tag ?
123. What is audio clip Interface and what are all the methods in it ?
124. What is the difference between getAppletInfo and getParameterInfo ?
125. How to communicate between applet and an applet ?
126. What is meant by event handling ?
127. What are all the listeners in java and explain ?
128. What is meant by an adapter class ?
129. What are the types of mouse event listeners ?
130. What are the types of methods in mouse listeners ?
131. What is the difference between panel and frame ?
132. What is the default layout of the panel and frame ?
133. What is meant by controls and types ?
134. What is the difference between a scroll bar and a scroll panel.
135. What is the difference between list and choice ?
136. How to place a component on Windows ?
137. What are the different types of Layouts ?
138. What is meant by CardLayout ?
139. What is the difference between GridLayout and GridBagLayout
140. What is the difference between menuitem and checkboxmenu item.

141. What is meant by vector class, dictionary class , hash table class,and property class ?

142. Which class has no duplicate elements ?
143. What is resource bundle ?
144. What is an enumeration class ?
145. What is meant by Swing ?
146. What is the difference between AWT and Swing ?
147. What is the difference between an applet and a Japplet
148. What are all the components used in Swing ?
149. What is meant by tab pans ?
150. What is the use of JTree ?
151. How can you add and remove nodes in Jtree.
152. What is the method to expand and collapse nodes in a Jtree
153. What is the use of JTable ?
154. What is meant by JFC ?
155. What is the class in Swing to change the appearance of the Frame in Runtime.
156. How to reduce flicking in animation ?
157. What is meant by Javabeans ?
158. What is JAR file ?
159. What is meant by manifest files ?
160. What is Introspection ?
161. What are the steps involved to create a bean ?
162. Say any two properties in Beans ?
163. What is persistence ?
164. What is the use of beaninfo ?
165. What are the interfaces you used in Beans ?
166. What are the classes you used in Beans ?
167. What is the diffrence between an Abstract class and Interface
168. What is user defined exception ?
169. What do you know about the garbate collector ?
170. What is the difference between C++ & Java ?
171. How do you communicate in between Applets & Servlets ?
172. What is the use of Servlets ?
173. In an HTML form I have a Button which makes us to open another page in 15 seconds. How will do you that ?
174. What is the difference between Process and Threads ?
175. How will you initialize an Applet ?
176. What is the order of method invocation in an Applet ?
177. When is update method called ?
178. How will you communicate between two Applets ?
179. Have you ever used HashTable and Dictionary ?
180. What are statements in JAVA ?
181. What is JAR file ?
182. What is JNI ?
183. What is the base class for all swing components ?
184. What is JFC ?
185. What is Difference between AWT and Swing ?
186. Considering notepad/IE or any other thing as process, What will Happen if you start notepad or IE 3 times? Where 3 processes are started or 3 threads are started ?
187. How does thread synchronization occurs inside a monitor ?
188. How will you call an Applet using a Java Script function ?
189. Is there any tag in HTML to upload and download files ?
190. Why do you Canvas ?
191. How can you push data from an Applet to Servlet ?
192. What are the benefits of Swing over AWT ?
193. Where the CardLayout is used ?
194. What is the Layout for ToolBar ?
195. What is the difference between Grid and GridbagLayout ?
196. How will you add panel to a Frame ?
197. What is the corresponding Layout for Card in Swing ?
198. What is light weight component ?
199. What is bean ? Where it can be used ?
200. What is difference in between Java Class and Bean ?
201. What is the mapping mechanism used by Java to identify IDL language ?
202. Diff between Application and Applet ?
203. What is serializable Interface ?
204. What is the difference between CGI and Servlet ?
205. What is the use of Interface ?
206. Why Java is not fully objective oriented ?
207. Why does not support multiple Inheritance ?
208. What it the root class for all Java classes ?
209. What is polymorphism ?
210. Suppose If we have variable ' I ' in run method, If I can create one or  More thread each thread will occupy a separate copy or same variable will be shared ?
211. What is Constructor and Virtual function? Can we call Virtual
212. Funciton in a constructor ?
213. Why we use OOPS concepts? What is its advantage ?
214. What is the difference in between C++ and Java ? can u explain in detail?
215. What is the exact difference in between Unicast and Multicast object ? Where we will use ?
216. How do you sing an Applet ?
217. In a Container there are 5 components. I want to display the all  the components names, how will you do that one ?
218. Why there are some null interface in java ? What does it mean ?
219. Give me some null interfaces in JAVA ?
220. Tell me the latest versions in JAVA related areas ?
221. What is meant by class loader ? How many types are there? When will we use them ?
222. What is meant by flickering ?
223. What is meant by cookies ? Explain ?
224. Problem faced in your earlier project
225. How OOPS concept is achieved in Java
226. Features for using Java
227. How does Java 2.0 differ from Java 1.0
228. Public static void main - Explain
229. What are command line arguments
230. Explain about the three-tier model
231. Difference between String & StringBuffer
232. Wrapper class. Is String a Wrapper Class
233. What are the restriction for static method Purpose of the file class
234. Default modifier in Interface
235. Difference between Interface & Abstract class
236. Can abstract be declared as Final
237. Can we declare variables inside a method as Final Variables
238. What is the package concept and use of package
239. How can a dead thread be started
240. Difference between Applet & Application
241. Life cycle of the Applet
242. Can Applet have constructors
243. Differeence between canvas class & graphics class
244. Explain about Superclass & subclass
245. What is AppletStub
246. Explain Stream Tokenizer
247. What is the difference between two types of threads
248. Checked & Unchecked exception
249. Use of throws exception
250. What is finally in exception handling  Vector class
251. What will happen to the Exception object after exception handling
252. Two types of multi-tasking
253. Two ways to create the thread
254. Synchronization
255. I/O Filter
256. Can applet in different page communicate with each other
257. Why Java is not 100 % pure OOPS ? ( EcomServer )
258. When we will use an Interface and Abstract class ?
259. How to communicate 2 threads each other ?
260. What is the difference between an Abstract class and Interface?
261. What is user defined exception?
262. What do you know about the garbage collector?
263. What is the difference between java and c++?
264. In an htm form I have a button which makes us to open another page in 15 seconds. How will you do that?
265. What is the difference between process and threads?
266. What is update method called?
267. Have you ever used HashTable and Directory?
268. What are statements in Java?
269. What is a JAR file?
270. What is JNI?
271. What is the base class for all swing components?
272. What is JFC?
273. What is the difference between AWT and Swing?
274. Considering notepad/IE or any other thing as process, What will happen if you start notepad or IE 3 times ? Where three processes are started or three threads are started?
275. How does thread synchronization occur in a monitor?
276. Is there any tag in htm to upload and download files?
277. Why do you canvas?
278. How can you know about drivers and database information ?
279. What is serialization?
280. Can you load the server object dynamically? If so what are the 3 major steps involved in it?
281. What is the layout for toolbar?
282. What is the difference between Grid and Gridbaglayout?
283. How will you add panel to a frame?
284. Where are the card layouts used?
285. What is the corresponding layout for card in swing?
286. What is light weight component?
287. Can you run the product development on all operating systems?
288. What are the benefits if Swing over AWT?
289. How can two threads be made to communicate with each other?
290. What are the files generated after using IDL to java compiler?
291. What is the protocol used by server and client?
292. What is the functionability stubs and skeletons?
293. What is the mapping mechanism used by java to identify IDL language?
294. What is serializable interface?
295. What is the use of interface?
296. Why is java not fully objective oriented?
297. Why does java not support multiple inheritance?
298. What is the root class for all java classes?
299. What is polymorphism?
300. Suppose if we have a variable 'I' in run method, if I can create one or more thread each thread will occupy a separate copy or same variable will be shared?
301. What are virtual functions?
302. Write down how will you create a Binary tree?
303. What are the traverses in binary tree?
304. Write a program for recursive traverse?
305. What are session variable in servlets?
306. What is client server computing?
307. What is constructor and virtual function? Can we call a virtual function in a constructor?
308. Why do we use oops concepts? What is its advantage?
309. What is middleware? What is the functionality of web server?
310. Why is java not 100% pure oops?
311. When will you use an interface and abstract class?
312. What is the exact difference in between Unicast and Multicast object? Where will it be used?
313. What is the main functionality of the remote reference layer?
314. How do you download stubs from Remote place?
315. I want to store more than 10 objects in a remote server? Which methodology will follow?
316. What is the main functionality of Prepared Statement?
317. What is meant by Static query and Dynamic query?
318. What are Normalization Rules? Define Normalization?
319. What is meant by Servelet? What are the parameters of service method?
320. What is meant by Session? Explain something about HTTP Session Class?
321. In a container there are 5 components. I want to display all the component names, how will you do that?
322. Why there are some null interface in JAVA? What does it mean? Give some null interface in JAVA?
323. Tell some latest versions in JAVA related areas?
324. What is meant by class loader? How many types are there? When will we use them?
325. What is meant by flickering?
326. What is meant by distributed application? Why are we using that in our application?
327. What is the functionality of the stub?
328. Explain about version control?
329. Explain 2-tier and 3-tier architecture?
330. What is the role of Web Server?
331. How can we do validation of the fields in a project?
332. What is meant by cookies? Explain the main features?
333. Why java is considered as platform independent?
334. What are the advantages of java over C++?
335. How java can be connected to a database?
336. What is thread?
337. What is difference between Process and Thread?
338. Does java support multiple inheritance? if not, what is the solution?
339. What are abstract classes?
340. What is an interface?
341. What is the difference abstract class and interface?
342. What are adapter classes?
343. what is meant wrapper classes?
344. What are JVM.JRE, J2EE, JNI?
345. What are swing components?
346. What do you mean by light weight and heavy weight components?
347. What is meant by function overloading and function overriding?
348. Does java support function overloading, pointers, structures, unions or linked lists?
349. What do you mean by multithreading?
350. What are byte codes?
351. What are streams?
352. What is user defined exception?
353. In an htm page form I have one button which makes us to open a new page in 15 seconds. How will you do that?        

Advanced Java

1. What is RMI?
2. Explain about RMI Architecture?
3. What are Servelets?
4. What is the use of servlets?
5. Explain RMI Architecture?
6. How will you pass values from htm page to the servlet?
7. How do you load an image in a Servelet?
8. What is purpose of applet programming?
9. How will you communicate between two applets?
10. What IS the difference between Servelets and Applets?
11. How do you communicate in between Applets and Servlets?
12. What is the difference between applet and application?
13. What is the difference between CGI and Servlet?
14. In the servlets, we are having a web page that is invoking servlets ,username and password? which is checks in database? Suppose the second page also if we want to verify the same information whether it will connect to the database or it will be used previous information?
15. What are the difference between RMI and Servelets?
16. How will you call an Applet using Java Script Function?
17. How can you push data from an Applet to a Servlet?
18. What are 4 drivers available in JDBC? At what situation are four of the drivers used?
19. If you are truncated using JDBC , how can you that how much data is truncated?
20. How will you perform truncation using JDBC?
21. What is the latest version of JDBC? What are the new features added in that?
22. What is the difference between RMI registry and OS Agent?
23. To a server method, the client wants to send a value 20, with this value exceeds to 20 a message should be sent to the client . What will you do for achieving this?
24. How do you invoke a Servelet? What is the difference between doPost method and doGet method?
25. What is difference between the HTTP Servelet and Generic Servelet? Explain about their methods and parameters?
26. Can we use threads in Servelets?
27. Write a program on RMI and JDBC using Stored Procedure?
28. How do you swing an applet?
29. How will you pass parameters in RMI? Why do you serialize?
30. In RMI ,server object is first loaded into memory and then the stub reference is sent to the client. true or false?
31. Suppose server object not loaded into the memory and the client request for it. What will happen?
32. What is the web server used for running the servelets?
33. What is Servlet API used for connecting database?
34. What is bean? Where can it be used?
35. What is the difference between java class and bean?
36. Can we sent objects using Sockets?
37. What is the RMI and Socket?
38. What is CORBA?
39. Can you modify an object in corba?
40. What is RMI and what are the services in RMI?
41. What are the difference between RMI and CORBA?
42. How will you initialize an Applet?
43. What is the order of method invocation in an Applet?
44. What is ODBC and JDBC? How do you connect the Database?
45. What do you mean by Socket Programming?
46. What is difference between Generic Servlet and HTTP Servelet?
47. What you mean by COM and DCOM?
48. what is e-commerce?