How is the storage of application components inside a Docker image implemented?

A Docker image is a layered filesystem where each layer adds changes to the previous one. Application components (such as compiled Java classes, libraries, configuration files) are placed inside the image as files and directories.

Typically, a Dockerfile specifies a base image (e.g., openjdk), then copies necessary application files into the container using the COPY or ADD command. Dependencies can also be installed, and the build process can be executed.

Example Dockerfile for a Java application:

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

Thus, all application components are stored inside the image as a filesystem, allowing the container to be run with a ready environment and application.