Chapter 45. The Application Plugin

The Gradle application plugin extends the language plugins with common application related tasks. It allows running and bundling applications for the jvm.

45.1. Usage

To use the application plugin, include in your build script:

Example 45.1. Using the application plugin


apply plugin:'application'

To define the main-class for the application you have to set the mainClassName property as shown below

Example 45.2. Configure the application main class


mainClassName = "org.gradle.sample.Main"

Then, you can run the application by running gradle run. Gradle will take care of building the application classes, along with their runtime dependencies, and starting the application with the correct classpath. You can launch the application in debug mode with gradle run --debug-jvm (see JavaExec.setDebug()).

The plugin can also build a distribution for your application. The distribution will package up the runtime dependencies of the application along with some OS specific start scripts. All files stored in src/dist will be added to the root of the distribution. You can run gradle installApp to create an image of the application in build/install/projectName. You can run gradle distZip to create a ZIP containing the distribution.

If your Java application requires a specific set of JVM settings or system properties, you can configure the applicationDefaultJvmArgs property. These JVM arguments are applied to the run task and also considered in the generated start scripts of your distribution.

Example 45.3. Configure default JVM settings


applicationDefaultJvmArgs = ["-Dgreeting.language=en"]

45.2. Tasks

The Application plugin adds the following tasks to the project.

Table 45.1. Application plugin - tasks

Task name Depends on Type Description
run classes JavaExec Starts the application.
startScripts jar CreateStartScripts Creates OS specific scripts to run the project as a JVM application.
installApp jar, startScripts Sync Installs the application into a specified directory.
distZip jar, startScripts Zip Creates a full distribution ZIP archive including runtime libraries and OS specific scripts.
distTar jar, startScripts Tar Creates a full distribution TAR archive including runtime libraries and OS specific scripts.

45.3. Convention properties

The application plugin adds some properties to the project, which you can use to configure its behaviour. See Project.

45.4. Including other resources in the distribution

One of the convention properties added by the plugin is applicationDistribution which is a CopySpec. This specification is used by the installApp and distZip tasks as the specification of what is to be include in the distribution. Above copying the starting scripts to the bin dir and necessary jars to lib in the distribution, all of the files from the src/dist directory are also copied. To include any static files in the distribution, simply arrange them in the src/dist directory.

If your project generates files to be included in the distribution, e.g. documentation, you can add these files to the distribution by adding to the applicationDistribution copy spec.

Example 45.4. Include output from other tasks in the application distribution


task createDocs {
    def docs = file("$buildDir/docs")
    outputs.dir docs
    doLast {
        new File(docs, "readme.txt").write("Read me!")

applicationDistribution.from(createDocs) {
    into "docs"

By specifying that the distribution should include the task's output files (see Section 15.9.1, “Declaring a task's inputs and outputs”), Gradle knows that the task that produces the files must be invoked before the distribution can be assembled and will take care of this for you.

Example 45.5. Automatically creating files for distribution

Output of gradle distZip

> gradle distZip
:processResources UP-TO-DATE


Total time: 1 secs