Deploy Java Web Application on Heroku with Heroku CLI

This post will describe how to create and deploy a Java Web Application war to Heroku using Heroku CLI. You will need a basic understanding of Git and Maven, and have Git and Maven already installed on your system.

Pre-requisites

• Install Java 8, Maven and Git. For this post, I used Java 8 and Maven 3.5.
• Create a free account on heroku.com. This account will be used from Heroku CLI to login
• Download and Install Heroku CLI from here.

Following are the high-level steps to follow

1. Create a Simple Spring Web Application.
2. Create an application on Heroku
3. Create the Procfile
4. Create app.json
5. Update Maven pom.xml
6. Push code to Heroku

Auto-Restart Spring Boot Application On Code Change With Dev Tools

Spring Boot Dev Tools enables auto-restarting a Spring boot application whenever any class is changed in the class path. This is not comparable in speed with the hot swap functionality offered by Jrebel or Spring Loaded, but this is a very simple and easy way to implement and better than manual restart. In this post, I use a simple Spring boot rest echo service to demonstrate how spring boot dev tools can be used to auto restart the application when using Maven on an IDE or Gradle from command line. In either options, the main trigger for a restart is the change to a class file, which means that the change to a Java file has to be compiled either by the IDE in option 1 or by Gradle in option 2.