Continuous Delivery in Java

Chapter 7. Packaging Applications for Deployment

You can deploy modern Java applications across a variety of platforms, and therefore it is beneficial to understand the fundamentals of how to best package applications using recommended artifact formats and practices. This chapter will walk you through building a JAR step-by-step, and along the way explore issues such as creating manifests, packaging dependencies (and classloading), and making a JAR executable. This information is fundamental for building artifacts for all platforms, even modern serverless ones. After this, you will explore other packaging options, such as fat JARs, skinny JARs, and WARs, and also lower-level OS artifacts like RPMs, DEBS, machine images, and container images.

Building a JAR: Step-by-Step

This chapter will be much easier to understand if you work through several concrete examples, and to help with this, a simple example project has been created with one dependency: the popular Logback logging framework. Maven will be used in the examples, but we will also mention how similar practices can be applied to other build tools. The example pom.xml for the project can be seen in Example 7-1.

Example 7-1. The super-simple example project pom.xml

 <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0"          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> ...