Monday, May 30, 2011

Interview Questions when 5 or 6 years of Java/J2EE experience

Interview Questions when 5 or 6 years of Java/J2EE experience

I attended so many interviews. I have around 6 years of IT industry experience, with 5 years in Java/J2EE. Attending interviews is good thing for me because it helps me revise the things, and I have switched many companies so nobody offers me a job, thats good, because I am also not willing to join or change, but for my acumen, and to keep myself ready, I attend interviews.
I believe apart from following blogs, forums, technocrats, interviews are also good way to be up to date.
Below are the questions asked several companies in India like Sapient, Royal Bank OF Scotland, Namura, HP, etc.
I would post the solutions to some tricky questions in following blogs.
Generally there were some basic questions:
1. java Objective SCJP level
2. J2EE objective
3. JMS Objective
4. IBM MQ Objective
5. Complicated Multithreading
6. Serialization, File I/O

Then in Face to Face, which generally is of more than 1 hr. Following are questions asked from different companies:

JDk 1.5 Collections classes.
Multintreading Concepts - Barrier, Latch, etc.
JMS functioning
SQl Query using JOINS
Java Design pattern - detail
Overloading, Overriding, Comparator, Comparable, hashCode(), equals(), Serializable, Externalizable, RMI, garbage Collection.

1. How would you implement cache in java.
2. How would you implement auto complete using java, jsp.
3. How would you implement a chache with auto complete feature.
4. How to make class immutable.
5. How to serialize immutable class.
6. How to gaurantee message delivery in JMS, fault tolerance
7. Message recovery techniques and redelivery.
8. DROP table.
9. Oracle Stored Procedure or function
10. Struts architecture
11. JSP Exception Handling
12. java Objective SCJP Level
13. java Design Pattern
14. J2EE objective
15. Implementing references
16. UNIX Commands - grep, softlink, hardlink
17. Serializable, Externalizable, Cloneable

1. How would you implement your own Thread Pool.
2. What is NIO
3. Best way to read data from socket using traditional I/O
4. Beat way to read file.
5. How to read characters from InputStream.
6. How Serialization works
7. Synchronization
8. how to implement counter in servlet.
9. how hashtable is thread safe.
10. CharSet, Enocder, Decoder
11. AtomicInteger, volatile, transient.
12. JTA, XA, how XA works, two phase commit.
13. Role of transaction manager in XA transaction.
14. XADataSource, and closing XADataSource.
15. UserTransaction
16. JCA Architecture

Mobily Infotech
1. deep copy and shallow copy
2. hash code
3. graceful shutdown of threads
4. NaN, 0/0
5. wrapper classes.
6. BootStrap Class Loader
7. Oracle OCI.
8. Oracle JDBC drivers
9. Oracle Thin and Thick Clients.
10. Oracle Rak
11. MQ API, MQ classes for Java.
12. MessageId, Priority for MQ message.
13. Garbage Collection
14. Java Green Threads
15. Coorelated Sub Queries.
16. Steps to make connection to MQ using Java.
17. Options to set for browsing message in MQ Queue.
18. Client Mode/Bindings Mode.
19. Log4j
ION Trading
1. Core Java SCJP level
2. Current Project Architecture
3. Message Flow in current project.
4. Fault Tolerance in JMS
5. Hashing Algo in Java, HashMap
6. Aggregation, Composition, Encapsulation, Abstraction.
7. How to implement Thread Pool
8. Complete Garbage Colection Algo.
9. DataSource, DB connection pool - how it works.
10. Exception- Logic, how to handle and design Exception, Error.
11. NIO-concept, Socket handling using NIO.
12. Adapter Design pattern
13. Stored Proc, Trigger
14. JDK1.5 Thread pool
15. Serialization, Externalization
16. Immutable, FInal, Usage of Final and Immutable
17. Exception handling in the spawned threads
18. RESTful Web Services, JEEVAN
19. Types of Parsers

1. Why Use EJB 3.0
2. Why use JPA
3. Why use JPA with ORM, Standard ORM products
4. Writing Complex Query while using JPA and ORM
5. JTA, how it works
6. JTA, how to use
7. Where to use JDBC and where ORM
8. JSF Architecture, who is model, view and controller
9. Optimistic Lock in JPA - Detailed
10. Multithreaded program to read large file/ code and design

1. Latch, Barrier, synchronized, Lock, ThreadPoolExecuter, Garbage Collection Algo.
2. Which forums do you follow,  Cloud Computing, How to improve programming and Coding skills.
3.  Design hrose racing application.
4. Struts, how to extend struts. Why to use Struts.
5.  Where to use messaging

Royal Bank Of Scotland:
1. Hashing Algorithm.
2. Search Algorithm
3. MVC design Pattern.
4. Multi threading Objectives.
5. Design Application which handles a particular operation for millions of trades, operation like trade validation. Application communicates external application for data.
6. Several Designing Questions.
7. Scala, Open Source high performing JMS implementations, Dynamic languages
8. Cache Implementation.
9. How Oracle Coherence works.

1. JCA - Tntro
2. JPA - Intro
3. EAGER/ LAZY loading
4. JPA relations
5. IBM MQ Objective
6. JMS session, Thread Safety In JMS
7. JMS providers
8. JMS implementation
9. AQ Provider and implementation using JNDI
10. Garbage Collection algorithms.
11. SOAP
12. JTA.

Bank Of America - Meriyl Lynch
1. How is semaphore implemented.
2. How to ensure only one instance in Singleton class.
3. How synchronization works, inside JVM.
4. Master JVM is holding objects. Slave JVM's are reading and writing the object.
     What problems can come and what is solution.
5. How Garbage Collection works in JVM.
6. When are class garbage collected, when are classes unloaded.
7. How to ensure that instance is never garbage collected.
8. Different protocols for Web Services.
9. Managing Session in Web Services
10. RMI, how EJB works
11. passing objects between two JVM's.

12. role of WSDL, stubs, etc. in Web Services.
13. Garbage Collection Tuning parameters.
14. LAZY Loading in ORM.
15. Why there is Stack and heap in JVM. Why this structure.
16. how much memory a program consumes, when no objects created inside program.
And more....

1. 50 numbers ( 1 to 50 ) are distributed in random order in an array of size 50. One number is missing. How to find. 
2. Inner Classes, Anonymous Classes. 
3. Find manager name who has max. number of employees working under him, when table has employeedID, Name, and ManagerID as columns. and Manager can also be employee. 
4. Serialization. 
5. How to design a web application, medium size. 
6. Write logic to print alternate elements in a ArrayList, even some are removed. 
7. How to implement a Hospital scenario, where doctor is examining patients, and emergency cases, and informing doctor of emergency cases, scheduling, etc. 
8. How to select unique elements from a table. 
9. Calculate number of legs, and give formula:
   7 persons, each person having 7 bags, each bag having 7 dogs, and each dog having 7 puppies.

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