Computacenter Interview Questions and Answers

Set is a collection of unique elements, List is an ordered collection of elements, and Map is a collection of key-value pairs.

• Set does not allow duplicates, e.g. a set of integers {1, 2, 3, 4, 5}

• List maintains the order of elements, e.g. a list of names ['John', 'Mary', 'Bob']

• Map stores key-value pairs, e.g. a map of phone numbers {'John': '123-456-7890', 'Mary': '987-654-3210'}

To train a beginner in Java, start with basic concepts and gradually introduce programming concepts.

• Start with basic concepts like data types, variables, and operators

• Introduce control structures like if-else statements and loops

• Teach object-oriented programming concepts like classes and objects

• Encourage practice and experimentation with simple programs

• Provide resources like online tutorials and exercises

• Offer guidance and feedback on their code

Main method is static because it needs to be called without creating an instance of the class.

• Static methods can be called without creating an instance of the class

• Main method is the entry point of the program

• Main method must have a specific signature: public static void main(String[] args)

• args is an array of strings that can be used to pass command line arguments to the program

Microservices are a software architecture approach where applications are built as a collection of small, independent services.

• Advantages include increased scalability, flexibility, and resilience

• Each service can be developed, deployed, and scaled independently

• Allows for easier maintenance and updates

• Basic architecture involves breaking down a monolithic application into smaller, self-contained services

• Services communicate with each other through APIs

To develop a Spring Boot application, follow these steps:

• Create a new Spring Boot project using Spring Initializr

• Define the necessary dependencies in the pom.xml file

• Create the necessary Java classes and packages

• Define the application properties in the application.properties file

• Run the application using the Spring Boot Maven plugin or by running the main class

• Test the application using a web browser or a REST client

JDK is a development kit, JRE is a runtime environment, and JVM is a virtual machine that executes Java code.

• JDK includes JRE and development tools

• JRE includes JVM and necessary libraries

• JVM interprets compiled Java code into machine code

• JDK is needed for developing Java applications

• JRE is needed for running Java applications

• Multiple JVMs can run on a single machine

Program to check if a number is prime or not.

• A prime number is only divisible by 1 and itself.

• Loop through numbers from 2 to n-1 and check if n is divisible by any of them.

• If n is divisible by any number, it is not prime.

• If n is not divisible by any number, it is prime.

JAVA API provides various classes and methods to handle data effectively.

• Use classes like BufferedReader, FileReader, and Scanner to read data from files.

• Use classes like BufferedWriter, FileWriter, and PrintWriter to write data to files.

• Use classes like ArrayList and HashMap to store and manipulate data in memory.

• Use classes like ResultSet and PreparedStatement to interact with databases.

• Use classes like JsonParser and JsonGenerator to handle JSON data.

• Use classes like Ciphe...read more