Building and Testing with Gradle

Chapter 2. Gradle Tasks

Inside of a Gradle build file, the fundamental unit of build activity is the task. Tasks are named collections of build instructions that Gradle executes as it performs a build. You’ve already seen examples of tasks in Chapter 1, and they may seem like a familiar abstraction compared to other build systems, but Gradle provides a richer model than you may be used to. Rather than bare declarations of build activity tied together with dependencies, Gradle tasks are first-class objects available to you to program if you desire.

Let’s take a look at the different ways of defining a task, the two key aspects of task definitions, and the task API we can use to perform our own customization.

Declaring a Task

In the introduction, we saw how to create a task and assign it behavior all at the same time. However, there’s an even simpler way to create a task. All you need is a task name (Example 2-1).

Example 2-1. Declaring a task by name only

task hello

You can see the results of this by running gradle tasks (Example 2-2).

Example 2-2. Gradle’s report of the newly created task

 ------------------------------------------------------------ Root Project ------------------------------------------------------------ Help tasks ---------- dependencies - Displays the dependencies of root project 'task-lab'. help - Displays a help message projects - Displays the subprojects of root project 'task-lab'. properties - Displays the properties of root project 'task-lab'. tasks - Displays the ...