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Best Java interview questions




Which are the most asked java interview questions ?

In: Uncategorized Asked By: aiboogie [228 Blue Star Level]

Answer #1

I’ll try to compile here a list of maybe the most / best java interview questions which are asked at java interviews, differentiated by the level of the candidate applying:

1. In general first questions should be regarding basic java knowledge (syntax, types,most used methods, synchronization, garbage collection, collections, simple design paterns, jdbc, SQL – maybe).
2. The next pack of questions should test the higher abilities of the developer, targeting more complicated languge related functionality(trick questions which imply a good language understanding, some exotic keywords like volatile, some exotic methods like intern, some more complex design patterns, difference between last versions of java, virtual machine implementations etc, rmi, idl, corba)
3. The 3rd pack sould contain questions about web, distributed and database development (jsp, servlets, struts, jsf, spring, hibernate, orm, differences between them – where is the case, design patterns, projects involved, soa, web services)
4. I add in the last pack general questions (like what IDEs have you used, what application servers have you used, comparison between them – where is the case, best and worst projects you’ve been into and why, motivation for changing the job for the present one etc)

**UPDATE**: If you are a junior java developer or an aspiring one, I strongly recommend you to take first the OCJP certification before going to an interview. This can increase your chances to succes big time, as well as your entry salary – proven and tested by myself! :)

1) Junior java developer
a) Basic ocjp (former scjp) questions:
– What does static, final mean, purposes;
– How many accesibility modifiers exist? Please describe them.
– Why do you need a main method?
– How many constructors can you have?
– Define overwriting and overloading
– Give java API implementations for overwriting and overloading
– Describe the String class – unique properties
– StringBuilder vs StringBuffer
– Collections : please describe, give some examples and compare them to eachother
– ArrayList vs Vector
– HashMap vs HashTable
– What’s a tree
– What’s a map
– Multithreading: describe the management in java
– What’s a semaphone?
– How many states are there for threads?
– Describe the usage for synchronized word (2)
– Serialization in java – a descrition and usage
– Garbage collection in java – description and usage
– Can you guarantee the garbage collection process?
b) Simple design pattern questions:
– Singleton please describe main features and coding
– Factory please describe main features and coding
– Have you used others? please describe them

2) Intermediate and Senior level – depending on rate of good responses, additional questions to 1):

a) Some other scjp:
– Describe transient
– Which other fields besies transient are not persisted?
– Describe volatile
b) Some logical assesments
– How can you isolate some variables in a multithreading environment without synchronized?
– Can you extend a class which is implementing the Singleton design pattern?
– Describe the Singleton pattern for a eager/laizy impelmentation and describe differences, pluses and minuses
– Give a thread safe version of Singleton
– Can you have more instances per one Singleton in a jvm?
– Diference between stateless and statefull – in general (not ejb-related)
– Difference between synchronous and asynchronous call in general (not ejb related)
c) Design patterns – additional questions
– Adaptor vs Wrapper design pattern
– Factory method design pattern
– Strategy design pattern
– Observer design pattern
d) Web development and enterprise knowledge
– D/HTML general questions
– What’s an EJB – how many typers are there
– How many types of JDBC drivers exist
– Describe JAAS
– Describe JAXB
– Descrive JAXP – difference to JAXB
– Describe Java Security in general
– What’s a webservice, how many ways of implementing it do you know?
– Describe SOA
– Why should you use SOA
– Descibe CORBA
– Describe SOAP
– Describe RMI
– What’s a stub? And a skeleton? Differences between them?
– What’s a Servlet?
– What’s a jsp?
– Difference between jsp and servlet
– Describe JSF
– What’s ORM
– Describe JPA
e) 3rd party frameworks
– What 3rd party frameworks do you know?
– Describe Struts 1
– Describe Struts 2
– Differences between Struts1, Struts 2 and JSF
– Describe Hibernate
– Describe Spring
f) others
– Tell me about teamwork
– What IDE’s have you used? Please describe and compare.
– What Applicaion Servers have you used? Please describe and compare.
– What companies have you worked for before? On which projects
– Please tell me the best project you were working at
– Please tell me the worst project you were woring at
– Please tell me why do you want to be a member of this team

You can find more questions and also the answers to these ones(in progress) at http://centraladvisor.com/tag/interview
and/or at http://centraladvisor.com/tag/java

Hope I awaken your interest, I wish you all success!

Answers Answered By: aiboogie [228 Blue Star Level]
Answer #2

i so glad about this list of questions. It’s very insteresting. Thank you so much to a development team

Answers Answered By: samuel Djiani [ Grey Star Level]

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