Can you explain the concept of multi-stage image building in Docker and its advantages?

Multi-stage build in Docker allows creating images in multiple steps, using intermediate images for building and then copying only the necessary artifacts into the final image.

Advantages:

• Reducing the size of the final image — only what is needed to run is included in the final image, without build tools and temporary files.
• Enhanced security — fewer components, fewer vulnerabilities.
• Convenience and cleanliness — build and run stages can be separated without creating multiple Dockerfiles.

Example:

# Build stage
FROM maven:3.8-jdk-11 AS build
WORKDIR /app
COPY pom.xml .
COPY src ./src
RUN mvn package

# Final image
FROM openjdk:11-jre-slim
WORKDIR /app
COPY --from=build /app/target/myapp.jar ./myapp.jar
CMD ["java", "-jar", "myapp.jar"]

Here, the application is first built using Maven, and then only the compiled jar is copied into the final image, without Maven and source files.