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Top 25 Java SE Interview Questions

1. what is a transient variable?

  •  A transient variable is a variable that whose value is not going to be serialized

2. What is synchronization?

  • With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources.
  •  Without synchronization, it is possible for one thread to modify a shared object while another thread is in the process of using or updating that object’s value. This often leads to significant errors.

3. What’s new with the stop(), suspend() and resume() methods in JDK 1.2? 

  • The stop(), suspend() and resume() methods have been deprecated in JDK 1.2.

4. Is null a keyword?

  •  "null"  is not a keyword. .null is a literal.

5. What state does a thread enter when it terminates its processing?

  • When a thread terminates its processing, it enters the dead state.

6. What is the Collections API?

  • The Collections API is a set of classes and interfaces that support operations on collections of objects.

7. What is the List interface?

  • The List interface provides support for ordered collections of objects which allows duplicate elements also.

8. What is the Vector class?

  • The Vector class provides the capability to implement a growable array of objects

9.Can we instantiate Abstract class?

  • We can not create object for abstract class directly. but indirectly through sub class object we can achieve it.

10.What is the first keyword used in a java program?

  • Its "package" keyword.

11.When a class should be defined as final?

  • If we do not want allow subclasses.
  • If we do not want to extend the functionality.

12.Can we declare abstract method as static?

  • No, we are not allowed to declare abstract method as static.
  • It leads to compilation error: illegal combination of modifiers abstract and static.

13.Can we apply abstract keyword to interface?

  • Yes, it is optional.
  • abstract interface A{}

14.Can we write empty interface?

  • Yes it is possible it is marker interface.
  • interface A{}
 

15.Can we declare interface as final?

  • No, it leads to compile time error. Because it should allow sub class.

16.How to solve ClassCastException?

  • To solve  ClassCastException we should use instanceof operator.
  • obj instanceof class_name

17. Is “xyz” a primitive value? 

  • No, it is not primitive it is string literal.

18.When is an object subject to garbage collection? 

  • An object is subject to garbage collection when it becomes unreachable to the program in which it is used.

19.What method must be implemented by all threads? 

  • The run() method, whether they are a subclass of Thread or implement the Runnable interface.

20.What happens if an exception is not caught?

  • An uncaught exception results in the uncaughtException() method of the thread’s ThreadGroup being invoked, which eventually results in the termination of the program in which it is thrown.

Job Opening: Mubble Networks Private Limited - 2015 Batch (through eLitmus)

Company: Mubble Networks Private Limited

 

Company URL: www.mubble.in

 

Position: Associate Product Developer

 

Job location: Bangalore

 

Event date: 25 Jun 2015

 

Last date to apply: 22 Jun 2015

 

Salary offered: Rs.500000/-

 

About the company: Mubble is a fast growing early stage start-up based in Bangalore with a mission to simplify mobile internet for the masses. Our first consumer App, a live and smart bill for prepaid smartphone users has clocked lakhs of downloads in less than two months after it came out of beta earlier this year

 

Eligibility:

 

  • 2015 batch B. Tech (CS,IT) 
  • Good academic record
  • Good pH score

 

 

Job Description: At Mubble, you will be building analytics based smartphone Apps that run on cloud computing infrastructure. You will be working on Android on one end, and programming on Amazon Web Services on another.   

Mobile, Cloud and Analytics – you will get to develop the three most sought after technology skills today. You will get to experience the “work hard play hard” culture of a fast growing start-up, with opportunities to wear multiple hats, and work closely with highly experienced founders.

 

 Desired Skills:

 

  • Excellent academics, leading college background will be a plus
  • Must have strong concepts in algorithms, data structures and software design
  • Programming experience with web technologies
  • Project experience on Android, Node.js will be helpful
  • Conceptual understanding of Amazon AWS / No-SQL also a plus

Job Opening: Jeronone Technologies - 2015 Batch (through Monster)

Skills: C, C++, Database, Javascript, Ajax, Core PHP, Wordpress , Joomla, Wordpress, Zend

Qualification: B. Tech (CS/IT) – 2015 Batch

Salary Details: INR 96000 to 2,40000 ( According to experience)

Designation: PHP Developers

Job Opening: Josh Technology Group - 2015 Batch (through AMCAT)

Company Name

Josh Technology Group

Profile Offered

Software Developer

Package Offered

CTC Up to Rs 6 LPA

Job Location

Gurgaon

Qualification/Batch

B.Tech (CS/IT/ECE/ECS) – 2015 Batch

Company Website

https://www.facebook.com/LifeAtJosh?ref=br_tf

Tentative Joining Date*

In June 2015

Tentative Test/ Interview Date*

Second week of March

Tentative Test/Interview Location*

Delhi/Uttar Pradesh/Haryana/Punjab/Rajasthan/Uttarakhand/Madhya Pradesh/Orissa