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Install JDK8 On Ubuntu Using Docker Build: Step-by-Step Guide

8 min read 11-15- 2024
Install JDK8 On Ubuntu Using Docker Build: Step-by-Step Guide

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To install JDK 8 on Ubuntu using Docker, you can simplify the process by following a step-by-step guide. Docker containers provide an isolated environment where you can run applications without worrying about the underlying operating system dependencies. In this post, we will walk through the entire process of installing JDK 8 on Ubuntu using Docker.

What is Docker?

Docker is an open-source platform that allows developers to automate the deployment of applications inside software containers. These containers can run on any operating system, ensuring consistency across various environments. With Docker, you can package your applications along with all their dependencies, which makes it easier to manage.

Why Use JDK 8?

Java Development Kit (JDK) 8 is one of the most widely used Java versions. It introduced significant improvements, including:

  • Lambda Expressions: Simplifying the development of concurrent applications.
  • Stream API: Enabling functional-style operations on collections.
  • Default Methods: Allowing methods to be added to interfaces without breaking existing implementations.

For many developers, JDK 8 remains an essential version for building Java applications.

Prerequisites

Before proceeding, make sure you have the following:

  1. Docker Installed: Ensure Docker is installed on your Ubuntu system. You can check if it's installed by running docker --version in the terminal.
  2. Basic Knowledge of Command Line: Familiarity with basic terminal commands will help you follow the guide smoothly.

Steps to Install JDK 8 on Ubuntu Using Docker

Step 1: Pull the Base Ubuntu Image

First, we need to pull the latest Ubuntu image from the Docker Hub. Open your terminal and run the following command:

docker pull ubuntu:latest

This command will download the latest Ubuntu image to your local machine.

Step 2: Create a Dockerfile

Next, we will create a Dockerfile that contains all the instructions to build our JDK 8 image.

  1. Create a new directory for your project:
    mkdir jdk8-docker
cd jdk8-docker
  2. Create a new file named Dockerfile:
    touch Dockerfile
  3. Open the Dockerfile in your favorite text editor and add the following content:
# Use the latest Ubuntu base image
FROM ubuntu:latest

# Set the environment variables
ENV JAVA_HOME /usr/lib/jvm/java-8-openjdk-amd64
ENV PATH $JAVA_HOME/bin:$PATH

# Install JDK 8 and other necessary packages
RUN apt-get update && \
    apt-get install -y openjdk-8-jdk && \
    apt-get clean;

# Verify the installation
CMD ["java", "-version"]

Step 3: Build the Docker Image

Now, let’s build the Docker image using the Dockerfile we just created. Run the following command in the terminal:

docker build -t jdk8-image .

This command will read the Dockerfile in the current directory (indicated by the .) and build an image named jdk8-image.

Step 4: Run the Docker Container

Once the image is built, we can run a container from this image to verify that JDK 8 is installed correctly. Execute the following command:

docker run --rm jdk8-image

The --rm flag ensures that the container is removed after it exits. If everything is set up correctly, you should see the installed version of Java, confirming that JDK 8 is successfully installed.

Step 5: Access the Container

If you want to run commands in the container interactively, you can start a bash shell in the container using:

docker run -it --rm jdk8-image /bin/bash

This will give you access to the command line within the container, allowing you to verify the JDK installation and run any Java commands.

Important Notes

The above instructions focus on installing the OpenJDK version of Java, which is recommended for most use cases.

Working with Java in Docker

Once you have JDK 8 installed in your Docker container, you can begin developing Java applications. Here’s a quick overview of how to create a simple Java application inside the container.

Step 1: Create a Java File

While inside the container, create a new Java file:

echo 'public class HelloWorld { public static void main(String[] args) { System.out.println("Hello, World!"); } }' > HelloWorld.java

Step 2: Compile the Java File

Now compile the Java file:

javac HelloWorld.java

Step 3: Run the Java Program

Finally, run your Java program:

java HelloWorld

You should see the output:

Hello, World!

Conclusion

Installing JDK 8 on Ubuntu using Docker is a straightforward process. By following the steps outlined in this guide, you can set up a development environment quickly and easily. Docker containers not only help maintain clean environments but also make it easier to manage dependencies and deployment configurations.

By utilizing Docker for your Java applications, you can ensure that your environment remains consistent across different machines and stages of development. Whether you’re building a microservice or a standalone application, Docker provides a powerful platform that can streamline your development workflow.

Now that you are equipped with the knowledge to install JDK 8 on Ubuntu using Docker, you can start building your Java applications with ease! Happy coding! 🚀

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