Docker Lab - HelloWorld

A sample Java program compiled and executed in a Docker container.

Running on the host machine

Prerequisites

• OpenJDK 11 or above

Build and run

1. Compile the Java source.

   javac HelloWorld.java

2. Run the Java program.

   java HelloWorld

   You will see the following printed out:

   Hello World!
   

Running in a Docker container

We will build a Docker image from the Dockerfile, then create a Docker container to run the Java program.

For more Dockerfile instructions, see Dockerfile reference.

Prerequisites

• Docker Desktop or Docker Engine

Build and run

1. Build the Docker image from the Dockerfile.

   docker build -t helloworld .

2. Run a Docker container from Docker image helloworld.

   docker run helloworld

   You will see the following printed out:

   Hello World!
   

   Then the Docker container will stop.

Docker CLI commands

For more commands, see Docker CLI reference.

Image

List images.

docker images

Remove one or more images.

docker rmi <IMAGE>

# Examples
docker rmi c53678d24ebc
docker rmi helloworld:latest

Remove dangling images.

docker image prune

Container

Run a container and run the command in the container.

docker run -it IMAGE COMMAND

# Examples
docker run helloworld ls

Run a container and start an interactive terminal session for the container. To exit out of the container's terminal session, type and enter exit.

docker run -it IMAGE

# Examples
docker run -it helloworld

List running containers.

docker ps

List all containers (running and stopped).

docker ps -a

Remove one or more containers.

docker rm CONTAINER

# Examples
docker rm a64c0c4ca0e9
docker rmi helloworld_container

Remove all containers (running and stopped).

docker rm $(docker ps -aq)