[Solved] Given this Dockerfile snippet:FROM openjdk:17-jdk-slim COPY target/app.jar /app.jar EXPOSE 8080 ENTRYPOINT ["java", "-jar", "/app.jar"]What happens when you run the built Docker image? | Spring Boot

Spring Boot - Docker and Deployment

Given this Dockerfile snippet:

FROM openjdk:17-jdk-slim
COPY target/app.jar /app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "/app.jar"]

What happens when you run the built Docker image?

AThe container runs but does not start the app

BThe container fails because EXPOSE is missing

CThe container runs the Spring Boot app on port 8080

DThe container runs the app but on port 80

Step-by-Step Solution

Solution:

Step 1: Analyze Dockerfile commands
FROM sets base image with Java 17. COPY adds app.jar. EXPOSE 8080 declares port. ENTRYPOINT runs the jar.
Step 2: Understand container behavior
When run, container starts Java app listening on port 8080 as declared.
Final Answer:
The container runs the Spring Boot app on port 8080 -> Option C
Quick Check:
ENTRYPOINT runs app, EXPOSE 8080 [OK]

Quick Trick: ENTRYPOINT runs app; EXPOSE shows port [OK]

Common Mistakes:

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