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Synechron Interview Questions – Set 1

September 20, 2017
Posted by Pumpkin

Synechron had arranged walk-in drive at Ahmedabad location for multiple opening at Mumbai, Pune and Bangalore location.  I have appeared for Sr Java Developer position.

I got a call from Ethos HR consultancy and interview was scheduled at the office of Ethos HR, Ahmedabad. Arrangement by Ethos HR was very poor and unprofessional. However, interviewers were very friendly and good at interviewing. 

There were total three rounds. Two technical and One HR round.

First Technical Round


  1. Do you know about SOLID design principles? Explain.
  2. What is the difference between ArrayList and LinkedList?
  3. When will ArrayList be resized? What will be the size of new ArrayList?
  4. How HashMap works internally? Explain hashCode() and equals() method? (Answer)
  5. How does HashMap calculate Bucket position, if returned HashCode of key is 35 and HashTable array size is just 16?
  6. Can we have multiple null values in HashMap?
    Answer : Yes. HashMap can have multiple null values and one null key. for more details you can check our article  on HashMap Internals.
  7. How does HashSet work internally? Which data structure it uses internally? 
    Answer : HashSet internally uses HashMap. Stores all the element as HashMap key and value as static instance of class Object.
    – For detailed understanding, please read our article  How is HashSet implemented internally in Java?
  8. What is the difference between HashMap, ConcurrentHashMap and SynchronizedMap?
    Answer : 
    HashMap is not thread-safe.

    – SynchronizedMap is a thread-safe, but it will acquire lock on entire Map in read and write opearations. So at a time only one thread can either read or write in Synchronized Map. Hence it is slower.

    ConcurrentHashMap is a thread-safe. Instead of acquireing a lock on entire Map object, it devides map in different segements and each thread can aquire a lock on individual segment. so at a time multiple threads can write in different segments but not in the same segement. Also this lock is required only in write operation.  Multiple threads can read concurrently from the same segement.

    HashMap and SynchronizedMap can have multiple null values and one null key whereas ConcurrentHashMap can not have any null keys or values. 

    – For detailed understanding, please read our article Hashtable Vs SynchronizedMap Vs ConcurrentHashMap

  9. What is the difference between CountDownLatchand CyclicBarrier? (Answer)
  10. How to create Immutable object? What you will do if one of the field in your immutable class is mutable?  (Answer


  1. Write down a program to implement your own iterator of ArrayList.
  2. Find a cycle in a linked list. 
  3. Find a first node of that cycle.
  4. Write a program to print 'Hello World' repeatadly using two threads. Thread 1 should print 'Hello' and Thread 2 should print 'World'


  1. Difference between POST and PUT method.
  2. Where have you used WebServices in your application?


  1. What are the scope of Spring Bean?
  2. What is the default scope of Spring Bean?
  3. What is prototype scope in Spring?
  4. Explain Spring MVC Execution Flow.
  5. Explain Spring Bean Life cycle.
  6. Explain any one use case of Spring BeanPostProcessor
  7. Difference between auto wire by Type and auto wire by Name.


  1. What is the use of group by and having Clause?
  2. Explain all types of joins in database.
  3. What is SQL Injection? Which feature of JDBC can we use to prevent SQL Injection?
  4. For below given SQL Table
Emp_Id Employee_Name Mgr_Id
100 Prateek
101 Kapil 100
102 Prakash 101
103 Jack 101

Write a query to fetch result as below

Employee_Name Manager_Name
Kapil Prateek
Prakash Kapil
Jack Kapil

HR Round

After I clear first technical round, they have scheduled a HR discussion. They have asked me about various behavioural questions like

  1. Why are you looking for a Job change?
  2. Why do you want to relocate to Bangalore?
  3. Why do you want to join Synechron?
  4. Have you read reviews about Synechron?
  5. There were so many negative reviews about Synechron in Glassdoor. Why you still want to join Synechron?
  6. where do you see yourself in 5 years?
  7. What are the two things which you don't like about your current organization?
  8. If we will give you an good offer, and after that your current organization will also agree to give you a good salary hike. Will you join Synechron or will choose to serve in current Organization?

Second Technical Round (Telephonic)

After HR Round, they have scheduled one more technical telephonic round.


  1. What all things will you take care, if you are using serialization?
  2. What will happen, if I will not declare SerialVersionUID in a class which implements Serializable?
  3. How have you used serialization in your project?
  4. What is the difference between Immutable object and Mutable Object?
  5. When you will use Immutable objects in your application?
  6. What is CyclicBarrier
  7. Have you ever used CyclicBarrierin your application? If Yes, what have you implemented using CyclicBarrier?
  8. Write a java function which accepts Map as input and outputs another Map.

input Map : Map<Student,Marks> 

output Map : Map<Student,Grades> 

conditions for output Map : 
1. Grades Calculation: 
     if marks > 90, then A Grade
     if 80 < marks < 90, then B Grade
     if 70 < marks < 80, then C Grade
     if 60 < marks < 70, then D Grade
     if 50 < marks < 60, then E Grade
2. Map should only contain Students having marks more than 50.
3. Map should be sorted based on Grades.


  1. What is the use of dispatcher servlet in Spring MVC.


  1. What all database constraint do you know?
  2. Is it possible to create Composite Unique Key? Or It can be created only on one table?
  3. Difference between clustered Index and Non clustered Index.


  1. What is First Level Caching in Hibernate?
  2. How you will create OneToMany relationship in Hibernate?
  3. What are the different state of Hibernate POJO?
  4. What is transient state?
  5. What is Cascade Attribute In Hibernate?

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Happy Learning 🙂

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