We need to start by creating a Maven pom.xml file. The pom.xml file contains the recipe that Maven uses to build your project. To create the pom.xml file, open your favorite text editor and add the following:

<?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">

	<modelVersion>4.0.0</modelVersion>

	<groupId>com.example</groupId>
	<artifactId>myproject</artifactId>
	<packaging>jar</packaging>
	<version>0.0.1-SNAPSHOT</version>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.2.RELEASE</version>
	</parent>

	<properties>
		<start-class>com.example.SampleTask</start-class>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
	</dependencies>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>
</project>

Creating a pom.xml file with the preceding content should give you a working build. You can test it by running mvn package (for now, you can ignore the "jar will be empty - no content was marked for inclusion!" warning ).

	Note
	At this point, you could import the project into an IDE (most modern Java IDE’s include built-in support for Maven). For simplicity, we continue to use a plain text editor for this example.

A Spring Cloud Task is made up of a Spring Boot application that is expected to end. In the pom.xml file we showed earlier, we created the shell of a Spring Boot application by setting our parent to use the spring-boot-starter-parent.

Spring Boot provides a number of additional “Starter POMs”. Some of them are appropriate for use within tasks (spring-boot-starter-batch, spring-boot-starter-jdbc, and others), and some may not be ('spring-boot-starter-web` is probably not going to be used in a task). The best indicator of which starter makes sense is whether the resulting application should end. Batch-based applications typically end. Conversely, the spring-boot-starter-web dependency bootstraps a servlet container, which better suits applications that continue.

For this example, we need only to add a single additional dependency — the one for Spring Cloud Task itself:

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-task</artifactId>
			<version>1.2.3.RELEASE</version>
		</dependency>

To finish our application, we need to create a single Java file. By default, Maven compiles the sources from src/main/java, so you need to create that folder structure. Then you need to add a file named src/main/java/com/example/SampleTask.java, as shown in the following example:

package com.example;

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.task.configuration.EnableTask;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableTask
public class SampleTask {

	@Bean
	public CommandLineRunner commandLineRunner() {
		return new HelloWorldCommandLineRunner();
	}

	public static void main(String[] args) {
		SpringApplication.run(SampleTask.class, args);
	}

	public static class HelloWorldCommandLineRunner implements CommandLineRunner {

		@Override
		public void run(String... strings) throws Exception {
			System.out.println("Hello, World!");
		}
	}
}

While it may seem small, quite a bit is going on. For more about Spring Boot specifics, see the Spring Boot reference documentation.

We also need to create an application.properties file in src/main/resources. We need to configure two properties in application.properties: We need to set the application name (which is translated to the task name), and we need to set the logging for Spring Cloud Task to DEBUG so that we can see what’s going on. The following example shows how to do both:

logging.level.org.springframework.cloud.task=DEBUG
spring.application.name=helloWorld

6.3.3 The CommandLineRunner

Spring includes many ways to bootstrap an application’s logic. Spring Boot provides a convenient method of doing so in an organized manner through its *Runner interfaces (CommandLineRunner or ApplicationRunner). A well behaved task can bootstrap any logic by using one of these two runners.

The lifecycle of a task is considered from before the *Runner#run methods are executed to once they are all complete. Spring Boot lets an application use multiple *Runner implementations, as does Spring Cloud Task.

	Note
	Any processing bootstrapped from mechanisms other than a CommandLineRunner or ApplicationRunner (by using InitializingBean#afterPropertiesSet for example) is not recorded by Spring Cloud Task.

At this point, our application should work. Since this application is Spring Boot-based, we can run it from the command line by using $ mvn spring-boot:run from the root of our application, as shown (with its output) in the following example:

$ mvn clean spring-boot:run
....... . . .
....... . . . (Maven log output here)
....... . . .


  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.3.3.RELEASE)

2016-01-25 11:08:10.183  INFO 12943 --- [           main] com.example.SampleTask                   : Starting SampleTask on Michaels-MacBook-Pro-2.local with PID 12943 (/Users/mminella/Documents/IntelliJWorkspace/spring-cloud-task-example/target/classes started by mminella in /Users/mminella/Documents/IntelliJWorkspace/spring-cloud-task-example)
2016-01-25 11:08:10.185  INFO 12943 --- [           main] com.example.SampleTask                   : No active profile set, falling back to default profiles: default
2016-01-25 11:08:10.226  INFO 12943 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a2c3676: startup date [Mon Jan 25 11:08:10 CST 2016]; root of context hierarchy
2016-01-25 11:08:11.051  INFO 12943 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2016-01-25 11:08:11.065  INFO 12943 --- [           main] o.s.c.t.r.support.SimpleTaskRepository   : Creating: TaskExecution{executionId=0, externalExecutionID='null', exitCode=0, taskName='application', startTime=Mon Jan 25 11:08:11 CST 2016, endTime=null, statusCode='null', exitMessage='null', arguments=[]}
Hello, World!
2016-01-25 11:08:11.071  INFO 12943 --- [           main] com.example.SampleTask                   : Started SampleTask in 1.095 seconds (JVM running for 3.826)
2016-01-25 11:08:11.220  INFO 12943 --- [       Thread-1] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@2a2c3676: startup date [Mon Jan 25 11:08:10 CST 2016]; root of context hierarchy
2016-01-25 11:08:11.222  INFO 12943 --- [       Thread-1] o.s.c.t.r.support.SimpleTaskRepository   : Updating: TaskExecution{executionId=0, externalExecutionID='null', exitCode=0, taskName='application', startTime=Mon Jan 25 11:08:11 CST 2016, endTime=Mon Jan 25 11:08:11 CST 2016, statusCode='null', exitMessage='null', arguments=[]}
2016-01-25 11:08:11.222  INFO 12943 --- [       Thread-1] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown

The preceding output has three lines that of interest to us here:

	Note
	A simple task application can be found in the samples module of the Spring Cloud Task Project here.