Running a Spring Boot Application — Spring Technical Interview Questions & Answers

IDE run, mvn spring-boot:run, and java -jar.

Running a Spring Boot Application

  • You can run a Boot app from IDE, Maven/Gradle, or a built JAR.
  • IDE: Run the class with main and SpringApplication.run(...).
  • Maven: mvn spring-boot:run.
  • JAR: java -jar target/your-app.jar after packaging.
  • Default web port is often 8080 unless you change server.port.
  • Port already in use — change server.port or stop the other process.
  • List all three run styles confidently.

Technical Interview Tip: IDE / Maven / java -jar — three ways to run.

Code Examples for Running a Spring Boot Application

Running a Spring Boot Application — working example

// Typical layout after Initializr (Maven):
// src/main/java/.../DemoApplication.java
// src/main/resources/application.properties
// pom.xml → spring-boot-starter-web

import org.springframework.boot.CommandLineRunner;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
class BootHooks {
  @Bean
  CommandLineRunner seed() {
    return args -> System.out.println("app ready: " + String.join(",", args));
  }
}

Running a Spring Boot Application — create projects via Initializr/STS; run the @SpringBootApplication main class or package an executable jar.

How to Explain Running a Spring Boot Application to an Interviewer

What is Running a Spring Boot Application (sb)?

Used for a short Running a Spring Boot Application sb example a small REST app Not just the heading

Give one small example of Running a Spring Boot Application (sb).

the smallest Running a Spring Boot Application sb example you can type IDE run, mvn spring-boot:run, and java -jar

What mistake do beginners make with Running a Spring Boot Application (sb)?

only saying “Running a Spring Boot Application sb” with no example Show the fix

Where do you use Running a Spring Boot Application (sb)?

a small REST app a short Running a Spring Boot Application sb example