Cognizant Java Developer Interview Questions and Answers

JDK, JVM, and JRE are core components of Java, each serving distinct roles in the development and execution of Java applications.

• JDK (Java Development Kit): A complete toolkit for Java development, including the compiler (javac), libraries, and tools for building Java applications.

• JRE (Java Runtime Environment): Provides the libraries and components necessary to run Java applications, but does not include developm...read more

A palindrome is a word, phrase, or sequence that reads the same backward as forward, like 'madam' or 'racecar'.

• Definition: A palindrome is a string that remains unchanged when reversed. Example: 'level', 'radar'.

• Ignoring Spaces and Punctuation: When checking for palindromes, spaces and punctuation are often ignored. Example: 'A man, a plan, a canal, Panama!'

• Case Sensitivity: Palindrome checks can be case insensiti...read more

Print each letter in a string along with the number of times it occurs

• Iterate through the string and count the occurrences of each letter

• Use a HashMap to store the letter as key and count as value

• Print the letter and count for each unique letter

Data can be retrieved from a database in Spring Boot using JPA repositories or JDBC templates.

• Use JPA repositories to create custom queries and retrieve data from the database.

• Use JDBC templates to execute SQL queries and retrieve data from the database.

• Configure the data source in the application.properties file.

• Use annotations like @Repository, @Entity, @Table, etc. to map Java objects to database tables.

To become a technical lead and contribute to the development of innovative solutions.

• I aim to continuously improve my technical skills and knowledge.

• I want to gain experience in leading a team and managing projects.

• I aspire to work on challenging projects that require creative problem-solving.

• I hope to make a positive impact on the company and its customers through my work.

• Example: I want to lead a team in develop...read more

HashMap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• HashMap uses hashing to store and retrieve values based on their keys.

• It uses an array of buckets to store the key-value pairs.

• The hash code of the key is used to determine the index of the bucket where the pair will be stored.

• If two keys have the same hash code, they are stored in the same bucket as a linked list.

• H...read more