Dockerfile for Spring Boot in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the base image for a Java 17 Spring Boot app.

Spring Boot

FROM [1]

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Aubuntu:20.04

Bpython:3.9

Copenjdk:17-jdk-slim

Dnode:18-alpine

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing a base image without Java.

Using an older Java version image.

The base image openjdk:17-jdk-slim provides Java 17 needed to run Spring Boot apps.

2fill in blank

medium

Complete the code to copy the Spring Boot jar file into the container.

Spring Boot

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

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Aapplication.properties

Bapp.jar

CDockerfile

Dpom.xml

Attempts:

3 left

💡 Hint

Common Mistakes

Copying configuration files instead of the jar.

Copying the Dockerfile by mistake.

The built jar file is usually named app.jar in the target folder.

3fill in blank

hard

Fix the error in the command to run the Spring Boot jar.

Spring Boot

CMD ["java", "-jar", "/app/[1]"]

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Aapp.jarr

Bapp

Capp.jar/

Dapp.jar

Attempts:

3 left

💡 Hint

Common Mistakes

Misspelling the jar file name.

Adding a slash after the jar file name.

The jar file name must be exact. app.jar is correct.

4fill in blank

hard

Fill both blanks to expose port 8080 and set the working directory to /app.

Spring Boot

WORKDIR [1]
EXPOSE [2]

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A/app

B8080

C/usr/src/app

D80

Attempts:

3 left

💡 Hint

Common Mistakes

Exposing the wrong port like 80.

Setting working directory to a different folder.

The working directory is set to /app where the jar is copied. Port 8080 is the default Spring Boot port.

5fill in blank

hard

Fill all three blanks to create a multi-stage Dockerfile: build with Maven, copy jar, and run it.

Spring Boot

FROM maven:3.8.7-openjdk-17 AS builder
WORKDIR /build
COPY [1] .
COPY src .
RUN mvn clean package -DskipTests
FROM openjdk:17-jdk-slim
WORKDIR [2]
COPY --from=builder /build/target/[3] .
CMD ["java", "-jar", "app.jar"]

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Apom.xml

B/app

Capp.jar

Dsrc

Attempts:

3 left

💡 Hint

Common Mistakes

Copying source code folder instead of pom.xml.

Setting wrong working directory in final stage.

Copying wrong jar file name.

We copy pom.xml to build the project, set working directory to /app, and copy the built app.jar from the builder stage.