Code360 powered by Coding Ninjas X Naukri.com. Code360 powered by Coding Ninjas X Naukri.com
Table of contents
1.
Introduction 
2.
Amdocs Java Developer Interview Questions for Freshers
2.1.
1. Explain the thread life cycle in Java.
2.2.
2. What is the final keyword refers in Java?
2.3.
3. What is a collection framework in Java?
2.4.
4. How is polymorphism implemented in Java?
2.5.
5. What is wrapper class?
2.6.
 6. What is a garbage collector in Java?
2.7.
7. Why is Java known as platform independent language?
2.8.
8. What is the difference between the TRUNCATE and DELETE commands?
2.9.
9. Explain the thread pool.
2.10.
10. Explain how Java supports linked lists.
2.11.
11. What are the differences between an overloading and an overriding
2.12.
12. What are the differences between a HashSet and a TreeSet?
3.
Amdocs Java Developer Interview Questions for Experienced
3.1.
13. What are the differences between HashMap and Hashtable?
3.2.
14. What is a Primary Key, Foreign Key & Unique Key in DBMS?
3.3.
15. What is the distinction between a Set and Map?
3.4.
16. Explain the approach to detect a loop in a linked list.
3.5.
17. What is the distinction between a List and a Set?
3.6.
18. Explain Normalization and Denormalization?
3.7.
19. How to remove duplicates in an ArrayList?
3.8.
20. What are the benefits of using OOPs?
3.9.
21. What are the differences between an ArrayList and a LinkedList?
3.10.
22. What are the limitations of Inheritance?
3.11.
23. Why do we override the equals() method?
3.12.
24. List the differences between an Array and an ArrayList in Java.
3.13.
25. What do you mean by hash-collision in Java?
4.
Coding Ninjas Resources 
5.
Frequently Asked Questions
5.1.
What is the duration of an interview process at Amdocs?
5.2.
What is the eligibility criteria for a Java developer at Amdocs?
5.3.
What are the benefits of working at Amdocs?
5.4.
What are the skills required to be a Java developer?
5.5.
What is the salary offered to Java developers at Amdocs?
6.
Conclusion
Last Updated: May 20, 2024

Amdocs Java Developer Interview Questions

Author Ayushi Goyal
0 upvote

Introduction 

Amdocs is a MNC (Multi National Company). It was founded by Boaz Dotan and Morris Kahn. Amdocs was founded in 1982 in Israel. The company was headquartered in Chesterfield, Missouri. Amdocs provides software and services to companies working in digital enterprise, media, communications, etc. In this article, we will discuss Amdocs java interview questions. So, let's have a look at what Java is.  

Amdocs Java Developer Interview Questions

Java is a programming language and platform that is quite popular and widely utilized. A platform is a software development and execution environment. Java is a quick, dependable, and secure language. Java is a high-level, object-oriented programming language. It was first introduced in 1995 by Sun Microsystems. Java runs on various platforms, including Windows, UNIX, Mac OS, etc. Java creates mobile/web/desktop apps, games, and more.

To become proficient and perform well in interviews, one must first master the foundations of the language. It includes learning how to answer the company's interview questions.

Let's study collections of questions on one of the widely used programming languages. Let’s discuss the most common Amdocs Java interview questions.


Click on the following link to read further: Java OOPs Interview Questions

Amdocs Java Developer Interview Questions for Freshers

Let’s start the discussion. So, here are some Amdocs Java developer Interview questions. 

1. Explain the thread life cycle in Java.

Ans: The thread cycle in Java consists of 5 states. These are:

  • New - It is also known as the born thread. It is the beginning of the thread life cycle. A new thread is created in this state. A thread stays in this state until it is started. 
  • Active - This state is also known as a runnable state. A thread that is about to run is sent to an active state. The thread scheduler decides the running time of the thread present here. 
  • Waiting/Blocked - This state is achieved when the thread is temporarily inactive. 
  • Timed Waiting - In this state, the thread moves to the waiting state for a specified time. 
  • Terminated - A thread when to this state after the task is completed. This state can also occur because of some error.

Thread life cycle

2. What is the final keyword refers in Java?

Ans: The final keyword is used to make java elements non-changeable. These elements can be a class, attribute, interface, or method. This final keyword is a modifier in Java. The element declared with the final keyword always stores same value.
 

3. What is a collection framework in Java?

Ans: The Collection framework in Java provides a framework for storing and managing a collection of objects. It gives developers access to prepackaged data structures and data manipulation algorithms. 
The following are part of the collection framework:
i) Interfaces
ii) Classes,
iii) Algorithms

These classes and interfaces support various operations such as searching, sorting, inserting, manipulating, and deleting, making data manipulation extremely simple and quick.
 

4. How is polymorphism implemented in Java?

Ans: The word Polymorphism is a combination of two words. 'Poly' means many, and 'Morphism' means forms. 

In Java, Polymorphism is categorized as -

  • Compile time Polymorphism: This is achieved by method overloading. This means multiple methods have the same name but different parameters. 
  • Run time polymorphism - This is achieved by method overriding. This means having the same methods in both child and parent classes.


5. What is wrapper class?

Ans: Wrapper class in Java is used for wrapping primitive data types in objects. This helps in using collection frameworks, as they store only objects. Also, objects are helpful for synchronization in multithreading. The classes of Java.util package only handles objects. So, the wrapper class makes it handy to use Java.util package. The wrapper classes of primitive classes are - 

Primitive classes

Wrapper classes

int

Integer

char

Character

short

Short

long

Long

float

Float

double

Double

byte

Byte

boolean

Boolean

 
6. What is a garbage collector in Java?

Ans: JVM(Java Virtual Machine) has a feature known as a garbage collector(GC). It automatically makes the unused memory reusable. The garbage collector removes the objects that are unreferenced from heap memory. It is based on the 'Stop-the-World process'. In this process, JVM stops the whole application for a specific duration and un GC. 

Along with advantages, GC can also affect the program's performance. It consumes more CPU resources to check free memory slots. Hence garbage collectors make our application slow. To measure the effect due to GC, we should keep our eyes on a few aspects - 

  • The number of occurrences of garbage collection. 
  • Duration for which garbage collector is running. 
  • The measure of resources used by garage collectors. 
  • Track if the garbage collection done is minor or complete. 
  • Percentage of time spent in garbage collection. 
  • The type of memory used. It can be heap or non-heap memory
     

7. Why is Java known as platform independent language?

Ans: Java uses a virtual machine known as Java virtual machine(JVM). When we compile our java code, this virtual machine converts it into byte code, as these byte codes can run on any platform. And Java uses these bytecode (.class) files to generate outputs. This functionality makes Java a platform-independent language.
 

8. What is the difference between the TRUNCATE and DELETE commands?

AnsDELETE is a command of Data manipulation language . While TRUNCATE is a command of the Data Definition Language. The differences between both are - 

TRUNCATE

DELETE

This command is used when we have to delete all the rows in the table. When we have to delta a specified number of rows, then DELETE is used. 
The TRUNCATE command is faster. The DELETE command is slower. 
Transaction space requirement is less. Transaction space requirement is more. 
This command deallocates the data to remove all the rows. This command removes one row at a time. Adds the record to the log table. 

9. Explain the thread pool.

Ans: In java, thread pool refers to a group of threads that can be reused. The size of a thread pool is fixed. The working is like a loop; threads are pulled from the pool. These threads are given to service providers. After completing the job given by the service provider, they are sent back to the thread pool. The thread pools help in saving a lot of time by making threads reusable. Also, thread pools are associated with some risks. These are - 

  • Deadlock is a condition in which many threads are waiting for another process. This occurs when each process is either waiting or holding some resource for a more extended time. 
     
  • Leakage - The risk of a thread being lost. This risk occurs when a thread is pulled out from the pool but not returned. 
     
  • Resource waiting time - This risk occurs when the thread pool size is enormous. In this, a significant portion of time is wasted, and the resources must wait longer. 
     

10. Explain how Java supports linked lists.

Ans: Java supports two forms of linked lists:

  • singly linked list is a form of data structure. Each node in a single linked list retains that node's contents and a reference to the next node in the List. There is no reference or pointer to the previous node stored.
     
  • The Doubly Linked List are a form of a linked list that allows traversal in both directions across the data items. This is made possible by each node having two links, one connecting to the next node and the other connecting to the previous node. 

 

11. What are the differences between an overloading and an overriding

Ans: Iterator traverses the elements only forward, whereas ListIterator traverses the elements both forward and backward.

Overloading

Overriding

Overloading is done within the same class.Overriding requires two classes, i.e., a parent class and one child class. 
There is no need of Inheritance in overloading. The concept of Inheritance is must for implementing overriding. 
The type or number of parameters must be different for each method. The type or number of parameters must be the same. 
The return type may be the same or not.The return type must be the same.
We can also change access and non-access modifiers. Access modifiers may be the same or increase. Non-access modifiers are only final and static.

You can also checkout Java List Iterator here

12. What are the differences between a HashSet and a TreeSet?

Ans: Both the HashSet and TreeSet implement the Set interface. The distinctions between the two are listed below-

  • TreeSet maintains ascending order, whereas HashSet does not.
  • TreeSet is implemented by a Tree structure, whereas a hash table supports HashSet.
  • HashSet outperforms TreeSet. In performance, HashSet is better.
  • TreeSet is supported by TreeMap, whereas HashMap supports HashSet.
Get the tech career you deserve, faster!
Connect with our expert counsellors to understand how to hack your way to success
User rating 4.7/5
1:1 doubt support
95% placement record
Akash Pal
Senior Software Engineer
326% Hike After Job Bootcamp
Himanshu Gusain
Programmer Analyst
32 LPA After Job Bootcamp
After Job
Bootcamp

Amdocs Java Developer Interview Questions for Experienced

13. What are the differences between HashMap and Hashtable?

Hashtable

HashMap

The Hashtable is synchronized.HashMap is not synchronized.
A Hashtable cannot have a ‘null’ key or a ‘null’ value.HashMap can have one or more ‘null’ keys and values.
Hashtable is ‘thread-safe’ and can be shared by multiple threads.HashMap is not ‘thread-safe’. As a result, it is appropriate for non-threaded applications. 
Dictionary Class is inherited by Hashtable.HashMap derives from AbstractMap.

14. What is a Primary Key, Foreign Key & Unique Key in DBMS?

Ans: 

Primary Key: It is a field or set of fields that identify a record uniquely in a database. This is a unique key in which a NOT NULL constraint is implied. This contraint specifies that primary key values cannot be NULL.
 

Foreign Key: A field or set of fields that refers to the primary key values in another table. A relationship between two tables must be established by referencing a foreign key with the primary key of another database. The table containing a foreign key refers to as the child table, while the table containing the primary key is referred to as the referenced or parent table. 
 

Unique Key: Each record in the database is recognized by a unique key. This key maintains the uniqueness of the column or collection of columns. A unique automatic constraint is defined as a primary key constraint. However, in the case of Unique Key, this is not the case. 
 

15. What is the distinction between a Set and Map?

Ans: The distinctions between the Set and the Map are listed below - 

  • Sets only contain values, whereas Maps contain both keys and values.
  • Sets have unique values, whereas Maps can have unique Keys but duplicate values.
  • Set has a single number of null values, whereas Map has a single null key with ‘n’ null values.
     

16. Explain the approach to detect a loop in a linked list.

Ans: Floyd's cycle finding algorithm is the best way to detect a loop in a linked list. This algorithm uses two pointers: a fast pointer and a slow pointer. The speed of the fast pointer is double that of the slow pointer. The steps to be followed include:

  • Traverse a linked list until slow or fast or fast of next is not null.
  • Increment the slow pointer by one. 
  • Increment the fast pointer by two. 
  • Check if both pointers are pointing to the same node. If this conditing is true, there exists a loop. Otherwise, the loop doesn't exist.
     

17. What is the distinction between a List and a Set?

Ans: The collection interface is extended by the List and Set. However, there exists some differences between the two, which are detailed below-

  • The List can have duplicate elements, whereas the Set has unique items.
  • The List is an ordered collection that keeps the insertion order, whereas the Set is an unordered collection that gives up the insertion order.
  • The List interface has a single legacy class, i.e., vector, whereas the Set interface does not have any legacy classes.
  • The List interface allows 'n' null values, whereas the Set interface only allows one null value.
     

18. Explain Normalization and Denormalization?

AnsNormalization is the process of structuring the columns and tables of a database. It helps in reducing redundancy and dependency. The primary goal of the normalization is to add, edit or delete the fields in a single table. The normalization is divided into five categories, which are described below:-

Normalization and Denormalization

1NF (First Normal Form): If every attribute in a relation is a single-valued attribute, the relation is in the first normal form. The first normal form is violated when a relation contains a composite or multi-valued attribute.


2NF (Second Normal Form): If a relation satisfies the conditions of first normal form and does not contain any partial dependency, it is in the second normal form. A relation in 2NF(Second Normal Form) has no partial dependency, which means that it has no non-prime attribute dependent on any proper subset of a candidate key in the table.
 

3NF (Third Normal Form): A relation is said to be in a 3NF(third normal form) if it meets the conditions for the Second normal form and does not contain any transitive dependency between the non-prime attributes, which means that all non-prime attributes are determined solely by the relation's candidate keys and not by any other non-prime attribute.
 

BCNF (Boyce Codd normal form): The advanced form of 3NF is BCNF. It's more stringent than 3NF. If every functional dependency X -> Y, X is the table's super key, the table is in BCNF. The table should be in 3NF for BCNF, and LHS is super important for every FD.


4NF (Fourth Normal Form): A relation is in 4NF if it satisfies the conditions of the third normal form and does not contain any multi-valued dependencies.


5NF (Fifth Normal Form): A relation that satisfies the conditions of 4NF and has no join dependencies, then it is in 5NF, and joining should be lossless. To avoid redundancy, 5NF is satisfied when all tables are divided into as many tables as possible. Project-join normal form (PJ/NF) is another name for 5NF.
 

Denormalization is a technique of accessing the database. It converts the data present in high normal forms to lower normal forms. This technique is also useful in combining data of related tables. Denormalization helps in adding redundancy if required.
 

19. How to remove duplicates in an ArrayList?

Ans: Duplicates in the ArrayList can be removed in two ways - 

  • Using HashSet: We can remove the duplicate element from the ArrayList using HashSet, but the insertion order will be lost.
     
  • Using LinkedHashSet instead of HashSet: We can also keep the insertion order by using LinkedHashSet instead of HashSet.

The LinkedHashSet method is used to remove duplicate elements from an ArrayList. The following steps can achieve the process of duplicating the elements:

  • ArrayList elements are copied to LinkedHashSet.
  • Then clear the ArrayList using the clear() method, which removes all elements from the list.
  • Now, copy all of the LinkedHashset elements to ArrayList.
     

20. What are the benefits of using OOPs?

Ans: OOPs allow for greater clarity in programming, making it easier to solve complicated problems.

  • Through inheritance, code can be reused, decreasing repetition.
  • Encapsulation binds data and code together.
  • Because OOPs enable data hiding, private information is kept hidden.
  • To make it easier to tackle problems can be broken down into smaller chunks.
  • Polymorphism allows the program to be more flexible by allowing entities to have numerous forms.
     

21. What are the differences between an ArrayList and a LinkedList?

Ans: Arraylist uses a dynamic array, while LinkedList uses a doubly link list -

Array list

Linked List

ArrayList is inefficient for manipulation because it requires too much.The manipulation of LinkedList is efficient.
Element manipulation is slower in ArrayList.Elements can be manipulated more quickly on LinkedList.
ArrayList is better for storing and retrieving data.To manipulate data, LinkedList is preferable.
It can only function as a List.Can function as both a list and a queue.
ArrayList allows for random access.The LinkedList does not support random access.
ArrayList uses less memory because it only stores objects. LinkedList has a higher memory overhead because it stores both the object and its address.

22. What are the limitations of Inheritance?

AnsYes, greater powers bring greater challenges. Inheritance is a great feature in OOPs, but it has some drawbacks. Inheritance takes longer to process since it must go through numerous classes to be implemented. Inheritance also involves two classes: a base class and a child class, which are extremely closely related. As a result, if changes are required, they may need to be made in both classes. Inheritance may be challenging to implement as well. As a result, if not implemented appropriately, this could result in unexpected errors or inaccurate outputs.


23. Why do we override the equals() method?

Ans: The equals method determines whether two objects are identical. We must override the objects based on the property if we want to check the objects.

For example, an Employee is a class with 3 data members: id, name, and salary. However, we want to test the equality of employee objects based on their salaries. The equals() method must then be overridden.


24. List the differences between an Array and an ArrayList in Java.

Ans: The differences between an array and an arraylist are: 

  • Arrays are a fundamental feature of Java. ArrayList is a collection system component in Java. It can be used to access array members, whereas ArrayList provides various methods for modifying and accessing components.
     
  • Although ArrayList is not a fixed-size data structure, Array is. There is no requirement to specify the size of an ArrayList object when creating it. Even after setting a maximum capacity, we can later add more parts.
     
  • Arrays can contain both class objects and primitive data types, depending on how they are defined. In contrast, ArrayList only accepts object and not primitive data types. The primitive int data type is converted to an Integer object when we use arraylist.add(1).
     
  • Since ArrayList cannot be constructed for primitive data types, its members always reference objects at different memory locations. As a result, the actual objects in an ArrayList are never stored in the same location. The references to actual items are kept close together. The type of array determines whether it is primitive or an object. Actual values for primitive types are continuous regions, while object allocation is equivalent to ArrayList.
     
  • Java ArrayList supports a wide range of other operations, including indexOf() and delete(). Arrays do not support these functions.
     

25. What do you mean by hash-collision in Java?

Ans: Hash-collision occurs when two keys with the same hash value collide. Two separate entries will be kept in a single hash bucket to avoid collision. 

There are two methods for avoiding hash collisions.

  • Open Addressing
  • Separate Chaining

Must Read Array of Objects in Java

Coding Ninjas Resources 

After discussing a lot of Amdocs Java Interview Questions. Now let’s see from where your can learn. We also have courses and articles containing popular questions from the Java syllabus. This will help you in clearing the Java developer interview. 
You can view our Java DSA course on -

Check out the most popular Java articles here.

Click here to check how to crack the technical interviews. Check Interview experience for top tech companies. Also, you can go through Top Computer Science Interview Questions and Answers.

You can also check out Has-A Relationship in Java here.
 

Here the Amdocs Java developer interview questions have come to an end. The areas covered in this Amdocs Java interview questions are the most sought-after skill sets in a Java Professional. These Amdocs Java interview questions will undoubtedly assist you in acing your next employment interview. 

Best wishes for your interview!

Frequently Asked Questions

What is the duration of an interview process at Amdocs?

The Amdocs interview process consists of 3-4 rounds. It takes around 1-2 weeks to be completed. Mostly, selected candidates get offer letters in 5-7 working days.

What is the eligibility criteria for a Java developer at Amdocs?

The candidate must have 60% in 10th, 12th, and graduation throughout. Moreover, there should not be any active backlog.  

What are the benefits of working at Amdocs?

Amdocs provides disability and life insurance. This shows their care for you and your family. The work-life balance is super exciting at Amdocs. The company also provides professional support by organizing programs and training. 

What are the skills required to be a Java developer?

To be a Java developer role, one must be proficient in Java. They must have sound knowledge of OOPS(Object Oriented Programming language). Also, knowledge of web technologies like HTML, CSS, JavaScript, etc, is a plus point.  

What is the salary offered to Java developers at Amdocs?

The salary of a Java Developer at Amdocs is around ₹7 lakhs per annum. The salary range from ₹3,21,804 - ₹10,64,933 per year. The salary figures mentioned above are subject to change.

Conclusion

In this blog, we learned about Amdocs Java interview questions and also went through each of the answers in detail that will assist you in preparing for your Java developer job interviews.

Check out here for other interview question blogs:


To learn more about Data Structures and Algorithms, you can enroll in our course on DSA in Java. Do upvote our blog to help other ninjas grow. 

Happy Learning, Ninja!

Previous article
R Programming Interview Questions
Next article
Amazon Behavioral Interview Questions
Live masterclass