ACI WORDLWIDE

1. Why we use Interface in Java? Give an example from your Project?

2. What is Abstract class ? what is the diffrence between Abstract class and interface?

3. What are the string operations you used in your project?

4. Write class which will do Validation of your classes but this validation class should be dynamic?

5. Write program which will remove duplicate elements from Array.

6. Write a Singleton Class.

7. What is Factory,Singleton,Proxy  Design Pattern?

8. What is IOC ?

9. What is Bean Factory?

10. What is Concurrent Hash Map?

11. What is the difference between HashMap and HashSet?

12. HashMap Internal Structure with Example?

13. What is evict in hibernate?

14 What is Generics why we use this in Java?

15 What is Assertion?

 

Cognizant

Round 1 Programs:

* Write a strategy which can be used to sort Employee object by age/first_name/last_name if no strategy is provided sort it by age.
* Write a program to create Deadlock.
* Write a program to print Fibonacci series.
* There are 2 threads T1 and T2.. T1 prints odd number 1,3,5,7 and T2 prints event number 2,4,6,8. Write a program using threads which will print following:
   1,2,3,4,5,6,7,8
* Write a program which will to sort Employee collection may be using merge sort.

Interview Round 1  and  2:

* What is ConcurrentHashMap?
* How to avoid reading from segment if some other thread is writing to same segment?
* What is difference between volatile and atomic? Which one should be used when?
* What is WeakHashMap?
* How to find deadlock in live code?
* What is Task?
* What is RentrantLock?
* What is livelock?
* Livelock is good or bad?
* Difference between aggregation and composition.
* What is difference between LinkedList and LinkedHashSet?
* What are the disadvantages of Threads?

Sela Question

Q1] what is java
ans : ddddd
Q2]