10+ Amdocs Senior Java Developer Interview Questions and Answers

Remove the Kth node from the end of a singly linked list.

• Traverse the linked list to find the length 'N'.

• Calculate the position to delete from the beginning as 'N - K + 1'.

• Delete the node at the calculated position.

• Handle edge cases like deleting the head or tail node.

Find the node where two linked lists merge

• Traverse both lists to find their lengths and the difference in lengths

• Move the pointer of the longer list by the difference in lengths

• Traverse both lists simultaneously until they meet at the merging node

Merge two sorted linked lists into a single sorted linked list with linear time complexity and constant space usage.

• Create a dummy node to start the merged list

• Compare the values of the two linked lists and add the smaller value to the merged list

• Move the pointer of the merged list and the pointer of the smaller value list forward

• Continue this process until one of the lists is fully traversed

• Append the remaining elements of the other list to the merged list

• Return the head of ...read more

Design a Least Recently Used (LRU) cache data structure that supports get and put operations with capacity constraint.

• Implement a doubly linked list to keep track of the order of keys based on their recent usage.

• Use a hashmap to store key-value pairs for quick access and update.

• When capacity is reached, evict the least recently used item before inserting a new item.

Java is platform-independent because the code is compiled into bytecode which can run on any platform with a JVM, making the JVM platform-dependent.

• Java code is compiled into bytecode, which is a platform-independent intermediate code

• The JVM interprets and executes the bytecode on different platforms

• The JVM acts as a layer of abstraction between the Java code and the underlying platform

• The JVM is platform-dependent because it needs to be implemented specifically for each plat...read more

The life cycle of a thread in Java involves creation, running, waiting, and termination.

• A thread is created using the 'new' keyword or by implementing the Runnable interface.

• The thread starts running when the start() method is called.

• During execution, a thread can enter a waiting state using methods like sleep() or wait().

• A thread terminates when its run() method completes or when the stop() method is called.

DELETE removes specific rows from a table, while TRUNCATE removes all rows and resets auto-increment values.

• DELETE is a DML command, while TRUNCATE is a DDL command.

• DELETE can be rolled back, while TRUNCATE cannot be rolled back.

• DELETE triggers delete triggers, while TRUNCATE does not trigger them.

• DELETE is slower as it logs individual row deletions, while TRUNCATE is faster as it logs the deallocation of the data pages.

• Example: DELETE FROM table_name WHERE condition; TRUNCAT...read more

Garbage collector in Java is a built-in mechanism that automatically manages memory by reclaiming unused objects.

• Garbage collector runs in the background to reclaim memory from objects that are no longer in use.

• It helps prevent memory leaks and optimize memory usage.

• Examples of garbage collectors in Java include Serial, Parallel, CMS, G1, and Z Garbage Collectors.

Railway Reservation System for booking train tickets

• Create a database to store train schedules, seat availability, and passenger information

• Develop a user interface for customers to search for trains, select seats, and make payments

• Implement a booking system to reserve seats and generate tickets

• Include features like seat selection, cancellation, and ticket printing

• Ensure security measures for payment processing and data protection

I use LinkedList for insertion and deletion as it provides constant time complexity.

• LinkedList provides constant time complexity for insertion and deletion operations.

• ArrayList provides linear time complexity for these operations.

• LinkedList is preferred when frequent insertion and deletion operations are required.

• ArrayList is preferred when frequent access to elements is required.

Finding non-duplicate element in a string program.

• Iterate through the string and count the occurrence of each character.

• Return the first character with count 1.

• If no such character found, return null or -1.

Association refers to a relationship between two or more objects where they are connected or linked in some way.

• Association is a fundamental concept in object-oriented programming.

• It is used to represent a relationship between two or more objects.

• The relationship can be one-to-one, one-to-many, or many-to-many.

• For example, a car has an association with its engine, as it cannot function without it.

• Another example is a student having an association with a school, as they attend...read more

Truncate removes all data from a table while delete removes specific rows.

• Truncate is faster than delete as it doesn't log individual row deletions.

• Truncate cannot be rolled back while delete can be.

• Truncate resets the identity of the table while delete doesn't.

• Truncate doesn't fire triggers while delete does.

Query to delete record in SQL

• Use DELETE statement with WHERE clause to specify the record to be deleted

• Make sure to backup data before deleting

• Example: DELETE FROM table_name WHERE column_name = value;