Mphasis Senior Java Developer Interview Questions, Process, and Tips

ExecutorService is an interface in Java that provides a way to manage and control the execution of threads in a multithreaded environment.

• It is part of the java.util.concurrent package.

• It provides methods to submit tasks for execution, manage thread pools, and control the execution of tasks.

• It allows for the execution of tasks asynchronously and provides features like scheduling, cancellation, and monitoring of tasks.

• E...read more

JPA is a Java specification for mapping Java objects to relational databases.

• JPA stands for Java Persistence API

• It provides a way to map Java objects to database tables and vice versa

• JPA simplifies the development of data access layer in Java applications

• It supports object-relational mapping (ORM) and allows developers to work with entities, relationships, and queries in a more object-oriented way

PreparedStatement is used in Java to execute parameterized SQL queries to prevent SQL injection attacks.

• PreparedStatement is a subinterface of Statement in Java.

• It is used to execute parameterized SQL queries.

• It helps prevent SQL injection attacks by automatically escaping special characters.

• Example: PreparedStatement pstmt = connection.prepareStatement("SELECT * FROM users WHERE username = ?");

Program to find missing numbers from Array

• Iterate through the array and store each number in a HashSet

• Then iterate from 1 to the length of the array and check if each number exists in the HashSet

• If a number is not found in the HashSet, it is a missing number

Find the first non-repeated character in a given string.

• Iterate through the string and store the frequency of each character in a hashmap.

• Iterate through the string again and return the first character with frequency 1.