How to Properly Dockerize Your Java Application?

Just to clarify, if you're hardcoding `localhost`, it's more of a coding issue than a Docker issue. But don't worry, we all start somewhere! It's great that you’re seeking help to do it the right way.

It's best to avoid hardcoding any external references. Instead, use environment variables to dynamically link to your resources. This way, your application can connect to either local Docker containers or even remote databases without a hitch.

The real issue here is having hardcoded hostnames in your app. To solve this, consider using system properties that you can set when starting your JVM. For instance, you could have something like this: `String hostname = System.getProperty("hostname", "localhost");`. This will allow your application to fallback to localhost only when no other hostname is specified, making it easier to switch between different environments. It’s a more flexible approach!

You definitely want to stick with one process per container and use Docker Compose for managing everything. Just make sure to adjust your Java application to reference the container names instead of localhost.

For Redis and MongoDB, you can use the official Docker images, so that shouldn't require much configuration unless you have specific needs. If you're concerned about data persistence, make sure to leverage external volumes in your Docker Compose setup to keep your data safe. Good luck!

Make sure to specify container names rather than using localhost, and keep all your containers on the same Docker network. For example, when you run your containers, you can do something like this: `docker run --name "app" --network myNetwork your_image_name`. This way, other containers can interact with it easily using the container name as a hostname.