README-java.md

Java Machine

This folder contains instructions to set up a containerized environment for running Java programs.

Usage

Starting the Container

1. Navigate to this folder
   Open your terminal and go to the folder containing the docker-compose.yml file.

2. Run the command:

    docker-compose up
   

Explanation: This command will download the necessary images, start the container, and run the Java application defined in Main.java.

Restarting the Application

If you want to test your application with new changes, you need to stop and rebuild the container.

1. Stop the containers and remove images:

    docker-compose down --rmi all
   

Explanation

Dockerfile

The Dockerfile is used to build the Java application image.

FROM openjdk:17-jdk-alpine

RUN apk add --no-cache bash

WORKDIR /app

COPY ./src /app/src

CMD ["java", "src/Main.java"]

Key Points:

• FROM openjdk:17-jdk-alpine: Uses a lightweight OpenJDK 17 image.
• RUN apk add --no-cache bash: Installs bash in the container.
• WORKDIR /app: Sets the working directory inside the container.
• COPY ./src /app/src: Copies your source code into the container.
• CMD ["java", "src/Main.java"]: Command to run the Java application.

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docker-compose.yml

The docker-compose.yml file defines how to run the container.

services:
  java:
    build: .
    container_name: java-app
    stdin_open: true
    tty: true

Key Points:

• services: Defines the services that run inside the container.
• java: Service name.
• build: .: Builds the image from the Dockerfile in the current directory.
• container_name: java-app: Assigns a name to the container.
• stdin_open: true and tty: true: Allow interactive console access inside the container.