Java /J2ee interview preparation

Preparation tips & links: (for 1st round interview) –Basic stuffsss …. More to add on… All d best!!!

*) Basic flow architecture of java – Read abt JVM, why we need JRE, Where we will be using JIT, CLASSLOADER workflow..

*) We should be good in core java concepts.. I would prefer to read Kathy serria (SCJP book).. Its not mandatory to take this SCJP exam, but its better to read this book atleast once and be familiar with all the topic.. Concentrate more on Threads,Generics & Collections (especially HashMap implementation).. I would urge you to code as much as possible.. Understand HashCode concept, implement a simple HashMap (what will happen if collision occurs in HashMap) , LoadFactor, rehash ,running time complexity(O(1)) .. Please check the source code of HashMap.java

*) Annotation – how to create a simple annotation (@Retention(RetentionPolicy.RUNTIME))

*) Task Scheduling Framework – [Executor & Future , Concurrent.* package ]

*) Interview questions – Arul kumaran (Search in Google, it’s a free source).. Read all the questions…

*) Design patterns… Please be familiar with 5-6 common pattern.. Singleton, Factory, Abstract Factory, Observable & Observer…
J2EE pattern – we should know basic things [ ServiceLocator , BussinessDelegate, DAO, SessionFacade ,FrontController ,Interceptor ]

http://www.javacamp.org/designPattern/

http://www.java2s.com/Code/Java/Design-Pattern/CatalogDesign-Pattern.htm

*) I have shared some more interview questions : here

*) JSP:

- Jsp life cycle
- Declaration <%! %>-understand the significance of !.. <%! String name=”vignesh”; %> is an instance variable declared outside _jspService() whereas <% String name=”vignesh”; %> is a local variable declared inside _jspService().
-Jsp page directive (import,isErrorPage,extends)
-Implicit variables (request,response,session,page ..etc)
- Custom Tag
- Difference between <%@include>

*) Servlet:
- GenericServlet, Servlet (check whether its a interface or class or abstract class).. Understand the core flow.. It sounds better, if we analyze these things..
- Life cycle
- ServletContext & ServletConfig (Imp)
- Cookie, UrlRewriting , session
- RequestDispatcher.forward() Vs HttpServletRe sponse.sendRedirect()
· forward- handled on server side. Transparent to browser
· redirect – sends redirect message to the browser
- Session affinity and sticky session in context of load balancing servers
- Understand about Http protocol
- Filter, Listener

Must read links:

J2EE-Clustering : here

Memory(OS memory + heap memory + outOfMemoryError) : here

Object creation in GC: here

Java Anti-Patterns : here

Supercharging your HashMaps & Pagination using JDBC and JSP: Both are discussed very briefly, one should understand abt this : here

Tuning Garbage Collection: (Must read and should know about young n tenured collection) here

String or Stringbuffer used as a key in HashMap .Which one is better: here

Reference (Strong,Weak,soft,Phantom) : here

How https can be used to maintain session state:here

Load balancing: here

Class format: here

Filter:here

Servlet: here

Javap: here

Please leave your comments , so that I can add more ques ..

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