Why containerization matters in Spring Boot - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a Spring Boot application main class.

Spring Boot

public class Application {
    public static void main(String[] args) {
        SpringApplication.[1](Application.class, args);
    }
}

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Alaunch

Bstart

Cexecute

Drun

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' or 'launch' instead of 'run' causes errors.

The SpringApplication.run() method starts the Spring Boot application.

2fill in blank

medium

Complete the Dockerfile line to specify the base image for a Spring Boot app.

Spring Boot

FROM [1]

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Anode:latest

Bubuntu:20.04

Copenjdk:17-jdk-slim

Dpython:3.12

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing non-Java images like Node or Python causes build failures.

Spring Boot apps run on Java, so the base image should be a Java JDK image like openjdk:17-jdk-slim.

3fill in blank

hard

Fix the error in the Dockerfile command to copy the jar file.

Spring Boot

COPY target/[1] /app/app.jar

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Aapp.jar

Bapplication.jar

Cmyapp.jar

Dspringboot.jar

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong jar file names causes Docker build errors.

The jar file built by Spring Boot is commonly named app.jar in this example, so the COPY command must match the actual jar filename.

4fill in blank

hard

Fill both blanks to complete the Dockerfile command that runs the Spring Boot app.

Spring Boot

ENTRYPOINT ["java", "[1]", "[2]"]

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A-jar

Bapp.jar

C-cp

Dtarget/app.jar

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-cp' instead of '-jar' or wrong jar file path.

The ENTRYPOINT runs the jar with java -jar app.jar.

5fill in blank

hard

Fill all three blanks to create a Docker command that builds and runs the container.

Spring Boot

docker [1] -t springboot-app . && docker [2] -d -p [3]:8080 springboot-app

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Abuild

Brun

C8080

Dstart

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'start' instead of 'run' or wrong port mapping.

First, build the image with docker build. Then run it detached with docker run -d mapping port 8080.