Support 'headless' applications

Update SpringApplication to run by default in 'headless' mode. This
prevents the AWT system from creating a Java icon (for example in the
OSX dock).

Also update builds to run tests in 'headless' mode.

spring-boot-cli/src/main/java/org/springframework/boot/cli/SpringCli.java

 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -90,6 +90,7 @@ public class SpringCli {
 	 * @return a return status code (non boot is used to indicate an error)
 	 */
 	public int runAndHandleErrors(String... args) {
+		System.setProperty("java.awt.headless", Boolean.toString(true));
 		String[] argsWithoutDebugFlags = removeDebugFlags(args);
 		boolean debug = argsWithoutDebugFlags.length != args.length;
 		try {

spring-boot-parent/pom.xml

@@ -359,6 +359,7 @@
 					</excludes>
 					<systemPropertyVariables>
 						<java.security.egd>file:/dev/./urandom</java.security.egd>
+						<java.awt.headless>true</java.awt.headless>
 					</systemPropertyVariables>
 					<argLine>-Xmx1024m -XX:MaxPermSize=256m</argLine>
 				</configuration>

spring-boot-samples/pom.xml

@@ -72,6 +72,21 @@
 					</additionalConfig>
 				</configuration>
 			</plugin>
+			<plugin>
+				<artifactId>maven-surefire-plugin</artifactId>
+				<configuration>
+					<includes>
+						<include>**/*Tests.java</include>
+					</includes>
+					<excludes>
+						<exclude>**/Abstract*.java</exclude>
+					</excludes>
+					<systemPropertyVariables>
+						<java.security.egd>file:/dev/./urandom</java.security.egd>
+						<java.awt.headless>true</java.awt.headless>
+					</systemPropertyVariables>
+				</configuration>
+			</plugin>
 		</plugins>
 	</build>
 	<repositories>

spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -177,6 +177,8 @@ public class SpringApplication {
 
 	private boolean webEnvironment;
 
+	private boolean headless = true;
+
 	private Set<ApplicationContextInitializer<?>> initializers;
 
 	private Set<ApplicationListener<?>> listeners;
@@ -305,6 +307,8 @@ public class SpringApplication {
 		stopWatch.start();
 		ConfigurableApplicationContext context = null;
 
+		System.setProperty("java.awt.headless", Boolean.toString(this.headless));
+
 		ApplicationEventMulticaster multicaster = createApplicationEventMulticaster();
 		try {
 			Set<Object> sources = getSources();
@@ -673,6 +677,15 @@ public class SpringApplication {
 		this.webEnvironment = webEnvironment;
 	}
 
+	/**
+	 * Sets if the application is headless and should not instantiate AWT. Defaults to
+	 * {@code true} to prevent java icons appearing.
+	 * @param headless if the application is headless
+	 */
+	public void setHeadless(boolean headless) {
+		this.headless = headless;
+	}
+
 	/**
 	 * Sets if the Spring banner should be displayed when the application runs. Defaults
 	 * to {@code true}.

spring-boot/src/main/java/org/springframework/boot/builder/SpringApplicationBuilder.java

 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.springframework.boot.builder;
 
 import java.util.Arrays;
@@ -59,7 +60,6 @@ import org.springframework.core.io.ResourceLoader;
  * SpringApplication instead.
  * 
  * @author Dave Syer
- * 
  */
 public class SpringApplicationBuilder {
 
@@ -307,6 +307,17 @@ public class SpringApplicationBuilder {
 		return this;
 	}
 
+	/**
+	 * Sets if the application is headless and should not instantiate AWT. Defaults to
+	 * {@code true} to prevent java icons appearing.
+	 * @param headless if the application is headless
+	 * @return the current builder
+	 */
+	public SpringApplicationBuilder headless(boolean headless) {
+		this.application.setHeadless(headless);
+		return this;
+	}
+
 	/**
 	 * Fixes the main application class that is used to anchor the startup messages.
 	 * 

spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

 /*
- * Copyright 2012-2013 the original author or authors.
+ * Copyright 2012-2014 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -398,6 +398,23 @@ public class SpringApplicationTests {
 		verify(applicationContext.getApplicationContext()).registerShutdownHook();
 	}
 
+	@Test
+	public void headless() throws Exception {
+		TestSpringApplication application = new TestSpringApplication(ExampleConfig.class);
+		application.setWebEnvironment(false);
+		application.run();
+		assertThat(System.getProperty("java.awt.headless"), equalTo("true"));
+	}
+
+	@Test
+	public void headlessFalse() throws Exception {
+		TestSpringApplication application = new TestSpringApplication(ExampleConfig.class);
+		application.setWebEnvironment(false);
+		application.setHeadless(false);
+		application.run();
+		assertThat(System.getProperty("java.awt.headless"), equalTo("false"));
+	}
+
 	private boolean hasPropertySource(ConfigurableEnvironment environment,
 			Class<?> propertySourceClass, String name) {
 		for (PropertySource<?> source : environment.getPropertySources()) {