Core Java Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

Core Java Interview Questions

Questions Answers Views Company eMail

Can we place the any object to key attribute of HashMap?

HCL,

4 18880

Hi friends, i am new to java. can you explain how java is secured.

2 4452

Hi Friends, can u give me Real Time example for interface and abstract class.(With Banking Example)

4 14681

when to use ArrayList and when to use HashMap in webApplication.

1 4610

what is main difference between architecture,framework and design pattren

3 15757

Hi Friends, can you explain instance in java. In general instance means "occurence of something" . In java what is instance.

4 5923

Hi Friends, I am beginner in java. what i know about synchonized keyword is,If more that one 1 thread tries to access a particular resource we can lock the method using synchronized keyword. Then after that how the lock is released and how next thread access that.Please explain with example.

5 6205

Hi Friends, can you give difference between extending thread class and implementing runnable interface.

4 6407

what is an object class?Explain its methods?

6 11699

Hi Friends, I am new to java. Can u explain about thread concept.How i know one thread is locked, and how can i force or acquire another thread for lock . Finally how to know thread is released from lock. Explain types of lock(like method level and block level) in thread.

1 3596

I have a sorting issue with a Hashmap. My constraint is that I MUST use the Hashmap and work with existing code. I do a database query and place the results in a Hashmap. When I iterate thru the Hashmap, it loses the original alphabetical sorting done by the database. So, my problem is that I must sort the results coming out of the Hashmap which is then placed into another class.

1 4404

What is Session and cookies?Explain in detail with an example?

Accenture, CTS,

4 19075

I need to know about complete topic in java's collections i with an examples

TCS,

1 4980

Real Time sample code for Encapsulation and Abstraction. where to use abstract and where to use specifies like public private.

2 9300

What will happen inside init() in servlet. my interviewer asked servlet lifecycle. i said "once servlet is loaded in to memory init() will be called which performs servlet initialization " . Again interview asked what values will be initialized . what is difference between init() and init(ServletConfig config).

Infinite Computer Solutions, TCS,

2 13179

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Un-Answered Questions { Core Java }

What environment variables are required to be set on a machine in order to run Java programs?

1140

Does java runtime require a license?

998

Why java is a platform independent? Explain

1023

Why parsing is done?

922

What are three advantages of using functions?

974

What does @param args mean in java?

1027

What is a void method?

886

How to make a non daemon thread as daemon?

1024

Write a program to print count of empty strings in java 8?

947

What is arraylist e in java?

1018

Which is fastest collection in java?

1018

What is java developer skills?

939

What is rule of accessibility in java?

971

What is boolean example?

909

What is the use of runnable interface?

1098

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