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Singleton

Singleton

    *Only one instance of class will be created

    Consider this class
    public class Singleton
    {
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Java Interview Part Two

Java Interview:

Prod Comp 2 :[2+yr][Programmer][Dec-2009]

I am glad to say that, I have cleared this interview(I got confirmation from this company).

Apart from telephonic interview, never messed up anywhere,
Be cool n relax, that’s d mantra…. Be confident, don’t be over confident..

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Java Interview Part One

Java interview questions:

I would like to share my interview exp with 2 product company situated in India..I am glad to say that, I have cleared both the interviews(I got confirmation from both company).. I will share those interview questions, so that it would be helpful for our preparation. Even though I have cleared the interview, I am looking forward to work in a project where it will involve some innovation.

Certifications help me a lot… Those who love java, I would request them to take Sun certification..It will help us to understand the concepts as well as its Pros & Cons.

Soon I will update the answers; at least I will give the pointers for the solutions…

Prod Comp 1:[2+ yr][Programmer][Jan-2010] Continue Reading »

JVM

Java Virtual Machine:

Main purpose : To run the compiled Java code across different network with out any modification.

Jvm doesn’t know abt Java language, it accepts only particular format (.class).A class file contains Java virtual machine instructions (bytecode) and a symbol table  as well as ancillary information.It can also be used to run other languages other than java.For example , Ada source code can be compiled to java bytecode and it can be executed by JVM.JVM executes .class files ,by using interpreter to emulate the instruction set or by using Just-in-Time compiler(JIT). JIT will not interpret and its used in most JVM to achieve greater speed.

JIT will convert bytecode into native machine code , thus it will improve the performance as well as it will caches the results of translating blocks (so it avoid reevaluating each line or operand each time it is met)..

How JVM Works :
-> Class will be loaded using ClassLoader(it will find the binary representation of classes).. Continue Reading »

Should I go for SCEA ?

Should I go for SCEA ?

I have 2 yr 4 months experience and I am planning to take this exam (need to prepare ).. Those who are planning to take this certification, I would suggest you to finish this certifications (SCBCD & SCDJWS), though its not mandatory, but it helps us to gain more knowledge..

Those who have exp more than 5 years can take this exam (Its suggested over here ).Its not mandatory and its purely your fondness to seize this certification.. Please don’t muddle up your talent with experience. Don’t take it (exp) has an obstacle instead take it as an challenge..

Note:
If I acquired SCEA certification, that doesn’t mean that I am a good architect. It helps\guide me to divide the problems into sub problems (which design pattern I have to apply) and it helps me to think like an architect….
But if you’re an experienced person and already came across this problem\issue, then its easy to resolve the issue (which patterns have to be applied and you will know the reason why we need to apply this pattern).

Experienced as well as SCEA Certified aspirant, please provide your valuable suggestions for this issue..

SCBCD 5

I would like to thank this Forum for the precious information I got from it as well as to Mikalai Zaikin (for his notes)..

How long did you prepare for this exam?
Almost 2 months. I have tried each and every topic with examples (Tutorials accessible in netbeans.org, I prefer to use Netbeans IDE..)

Material which I have used?
*Enterprise Java Beans (EJB) 3 In Action – Since I am novice, I have started with this book. Meticulously documented and lucidly written, this book is worthwhile for SCBCD.
*Ejb-3_0-fr-spec-ejbcore – EJB Spec provided by Sun
*Ejb-3_0-fr-spec-persistence -JPA Spec provided by Sun

Don’t try to resist yourself with book read ,need more hands on, otherwise its hard to remember all those classes, methods as well as annotations.

Note:
Difficulty level of SCDJWS 5 exam is very high when compared to SCBCD 5 (It is purely my opinion )..

Few More Study materials: Continue Reading »

We can access private variable of super class or any class using reflection api. I have created a sample class which will change the value of private variable to the new value. You need to set accessible flag as true in setAccessible() method of Field reflection class, then only it will allow us to read/change the private variable . There is one more way to suppress the access using SecurityManager class.
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Java CLassLoader

ClassLoader

ClassLoader is responsible for finding and loading class file at run time.ClassLoader class is located in java.lang package.we can subclass it to our functionality for class loading

Whenever a new JVM is started ,
> Bootstrap class loader is responsible for loading java classes like java.lang.Object and other runtime code into memory first.Runtime classes are in rt.jar file
>next comes java extension class loader(path java.ext.dirsExtClassLoader).
here we can place our .jar files since it will be loaded automatically when jvm starts
>lastly ,AppClassLoader which will load classes kept in the java.class.path System property

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SCWCD 5

SCWCD step by step :

Books to read:

1 .Head First JSP and Servlets 2nd Edition by Kathy Sierra and Bert Bates
2 . SCWCD Exam Study Kit: Java Web Component Developer Certification [
by Hanumant Deshmukh (Author), Jignesh Malavia (Author)
3) Follow javaranch website regularly, you will get entire details about all Sun certifictaions..

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SCDJWS 5

SCDJWS

Yesterday I took this SCDJWS 5 (310-230) exam and I got around 70%  (45 questions correct /65).Most of the questions are related to design architecture and theory part  . Only few questions (may be 2 or 3) had code snippets, related to creation of SOAP and SAX processor. I didn’t find a single code snippet for JAX WS(thousands of annotations ),XSLT,JAXB,DOM,JAXP,JAXR,REST  ..Check out interoperability issues when we integrating Java Web service with WCF.

I would like to thank JavaRanch Forum for the precious information I got from it as well as to IVAN (who shared his reference material guide) , Sang Shin(Java Passion) and Mikalai Zaikin ..

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