<h2 data-next-message="I'm ready to start">Introduction</h2>

Hang on for a few more minutes to learn how it all works, so you can make the most out of Heroku.

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<div class="only-windows">On Windows, start the Command Prompt (cmd.exe) or Powershell to access the command shell.</div>

In this step, you will prepare a sample application that's ready to be deployed to Heroku.

To create a local copy of a sample app that you can deploy to Heroku, execute the following commands in your local command shell or terminal:

Press `CTRL+C` to stop streaming logs.

<h2 data-next-message="I know how to scale my app">Scale the app</h2>

You can check how many dynos are running using the `heroku ps` command:

By default, your app is deployed on a free dyno. Free dynos sleep after thirty minutes of inactivity (i.e., if they don't receive any traffic). This causes a delay of a few seconds for the first request upon waking. Subsequent requests will perform normally.

To avoid dyno sleeping, you can upgrade to a hobby or professional dyno type as described in [Dyno Types](dyno-types). For example, if you migrate your app to a professional dyno, you can easily scale it by running a command telling Heroku to spin up a specific number of dynos, each running your web process type.

Scale it up again:

<h2 data-next-message="I've installed the app dependencies locally">Declare app dependencies</h2>

If you do not have Maven installed, or get an error like `'mvn' is not recognized as an internal or external command`, then you can use the wrapper command instead by running `mvnw clean install` on Windows or `./mvnw clean install` on Mac and Linux. This both installs Maven and runs the Maven command.

If you aren't using Spring in your app, you can accomplish this with the following plugin configuration in the `pom.xml` file.

Just like the Heroku platform, `heroku local` examines your `Procfile` to determine what command to run.

To stop the app from running locally, go back to your terminal window and press `CTRL+C` to exit.

At runtime, config vars are exposed to your app as environment variables. For example, modify `src/main/java/com/example/Main.java` so that the method obtains an energy value from the `ENERGY` environment variable:

:::>> file.append("src/main/java/com/example/Main.java#56")

@RequestMapping("/hello")

String hello(Map<String, Object> model) {

The `heroku run` command lets you run maintenance and administrative tasks on your app in a [one-off dyno](one-off-dynos). It can also lets you launch a REPL process attached to your local terminal for experimenting in your app's environment, or code that you deployed with your application:

If you receive an error, `Error connecting to process`, then you might need to [configure your firewall](one-off-dynos#timeout-awaiting-process).

The code to access the database is straightforward. Here's the method to insert values into a table called `tick`:

This ensures that when you access your app using the `/db` route, a new row is added to the `tick` table, and all rows are then returned so that they can be rendered in the output.