Extrieve Technologies Interview Questions and Answers

Basic java questions

Q1. Explain Linked list implementation and stack
Ans. 
Linked list is a data structure where each element points to the next element. Stack is a data structure that follows Last In First Out (LIFO) principle.
• Linked list implementation involves creating nodes with data and a pointer to the next node.

• Stack implementation involves pushing elements onto the stack and popping them off in reverse order.

• Example: Linked list - 1 -> 2 -> 3 -> NULL, Stack - push(1), push(2), push(3)
Answered by AI
Add your answer
Q2. Oops concepts in java
Ans. 
Oops concepts in Java refer to Object-Oriented Programming principles like Inheritance, Encapsulation, Polymorphism, and Abstraction.
• Inheritance: Allows a class to inherit properties and behavior from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Polymorphism: Ability of a method to do different things based on the object it is acting upon.

• Abstraction: Hiding the imp...read more
Answered by AI
Add your answer

Q1. What is JPA
Ans. 
JPA (Java Persistence API) is a specification for managing relational data in Java applications using object-relational mapping.
• JPA provides a way to map Java objects to database tables.

• It simplifies database interactions through an object-oriented approach.

• Common implementations include Hibernate, EclipseLink, and OpenJPA.

• Example: Using JPA annotations like @Entity to define a persistent class.

• JPA supports querying wi...read more
Answered by AI
Add your answer
Q2. Write a program to find duplicate elements in the list
Ans. 
This program identifies and returns duplicate elements from a given list.
• Use a set to track seen elements and a list for duplicates.

• Iterate through the list and check if an element is in the set.

• If it is, add it to the duplicates list; otherwise, add it to the set.

• Example: For the list [1, 2, 3, 2, 4, 3], the output should be [2, 3].
Answered by AI
Add your answer