Use server.port=0 for scanning

This leverages existing capabilities of teh JDK and the OS
to grab a port at random and not have it stolen by another
process. It's very hard to avoid that race condition in
pure Java code, so why bother?

User can set port<0 to disable autoStart of connectors (e.g.
to start a web application context but not have it listen on
any port). In that case the actual socket port will be set to
0 (and therefore if it ever starts up the local port will
be random).

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/ServerProperties.java

@@ -35,7 +35,6 @@ import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomize
 import org.springframework.boot.context.embedded.tomcat.TomcatContextCustomizer;
 import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
 import org.springframework.boot.context.properties.ConfigurationProperties;
-import org.springframework.util.SocketUtils;
 import org.springframework.util.StringUtils;
 
 /**
@@ -54,8 +53,6 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 
 	private Integer sessionTimeout;
 
-	private boolean scan = false;
-
 	@NotNull
 	private String contextPath = "";
 
@@ -81,14 +78,6 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 		this.port = port;
 	}
 
-	public boolean getScan() {
-		return this.scan;
-	}
-
-	public void setScan(boolean scan) {
-		this.scan = scan;
-	}
-
 	public InetAddress getAddress() {
 		return this.address;
 	}
@@ -112,9 +101,6 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 	@Override
 	public void customize(ConfigurableEmbeddedServletContainerFactory factory) {
 		Integer port = getPort();
-		if (this.scan) {
-			port = scanForPort(port);
-		}
 		if (port != null) {
 			factory.setPort(port);
 		}
@@ -132,26 +118,6 @@ public class ServerProperties implements EmbeddedServletContainerCustomizer {
 		}
 	}
 
-	private Integer scanForPort(Integer port) {
-		boolean found = false;
-		int delta = 1;
-		port = port == null ? 8080 : port;
-		while (!found) {
-			try {
-				port = SocketUtils.findAvailableTcpPort(port, port + delta);
-				found = true;
-			}
-			catch (IllegalStateException e) {
-				if (delta > 65536) {
-					throw e;
-				}
-				delta = delta > 5 ? delta > 100 ? delta * 4 : delta * 3 : delta * 2;
-			}
-			port = port + delta;
-		}
-		return port;
-	}
-
 	public static class Tomcat {
 
 		private String accessLogPattern;

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/ServerPropertiesTests.java

@@ -24,12 +24,9 @@ import java.util.Map;
 import org.junit.Test;
 import org.springframework.beans.MutablePropertyValues;
 import org.springframework.boot.bind.RelaxedDataBinder;
-import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainerFactory;
-import org.springframework.boot.context.embedded.MockEmbeddedServletContainerFactory;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
 
 /**
  * Tests for {@link ServerProperties}.
@@ -71,24 +68,6 @@ public class ServerPropertiesTests {
 				.getProtocolHeader());
 	}
 
-	@Test
-	public void testPortScan() throws Exception {
-		this.properties.setScan(true);
-		this.properties.setPort(1000);
-		ConfigurableEmbeddedServletContainerFactory factory = new MockEmbeddedServletContainerFactory();
-		this.properties.customize(factory);
-		assertTrue(factory.getPort() > 1000);
-	}
-
-	@Test
-	public void testPortScanFromHigher() throws Exception {
-		this.properties.setScan(true);
-		this.properties.setPort(5678);
-		ConfigurableEmbeddedServletContainerFactory factory = new MockEmbeddedServletContainerFactory();
-		this.properties.customize(factory);
-		assertTrue(factory.getPort() < 6000);
-	}
-
 	// FIXME test customize
 
 }

spring-boot-javadoc/pom.xml

@@ -50,7 +50,7 @@
 							<execution>
 								<id>aggregate-javadocs</id>
 								<goals>
-									<goal>jar</goal>
+									<goal>aggregate-jar</goal>
 								</goals>
 								<configuration>
 									<includeDependencySources>true</includeDependencySources>

spring-boot/src/main/java/org/springframework/boot/context/embedded/AbstractEmbeddedServletContainerFactory.java

@@ -82,7 +82,6 @@ public abstract class AbstractEmbeddedServletContainerFactory implements
 	 * @param port the port number for the embedded servlet container
 	 */
 	public AbstractEmbeddedServletContainerFactory(int port) {
-		checkPort(port);
 		this.port = port;
 	}
 
@@ -94,7 +93,6 @@ public abstract class AbstractEmbeddedServletContainerFactory implements
 	 */
 	public AbstractEmbeddedServletContainerFactory(String contextPath, int port) {
 		checkContextPath(contextPath);
-		checkPort(port);
 		this.contextPath = contextPath;
 		this.port = port;
 	}
@@ -129,16 +127,9 @@ public abstract class AbstractEmbeddedServletContainerFactory implements
 
 	@Override
 	public void setPort(int port) {
-		checkPort(port);
 		this.port = port;
 	}
 
-	private void checkPort(int port) {
-		if (port < 0 || port > 65535) {
-			throw new IllegalArgumentException("Port must be between 1 and 65535");
-		}
-	}
-
 	/**
 	 * Returns the port that the embedded servlet container should listen on.
 	 */

spring-boot/src/main/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainer.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.context.embedded.jetty;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.eclipse.jetty.server.Connector;
 import org.eclipse.jetty.server.Server;
 import org.springframework.boot.context.embedded.EmbeddedServletContainer;
@@ -28,10 +30,13 @@ import org.springframework.util.Assert;
  * {@link JettyEmbeddedServletContainerFactory} and not directly.
  * 
  * @author Phillip Webb
+ * @author Dave Syer
  * @see JettyEmbeddedServletContainerFactory
  */
 public class JettyEmbeddedServletContainer implements EmbeddedServletContainer {
 
+	private final Log logger = LogFactory.getLog(JettyEmbeddedServletContainer.class);
+
 	private final Server server;
 	private boolean autoStart;
 
@@ -81,6 +86,7 @@ public class JettyEmbeddedServletContainer implements EmbeddedServletContainer {
 			Connector[] connectors = this.server.getConnectors();
 			for (Connector connector : connectors) {
 				connector.start();
+				this.logger.info("Jetty started on port: " + connector.getLocalPort());
 			}
 		}
 		catch (Exception ex) {

spring-boot/src/main/java/org/springframework/boot/context/embedded/jetty/JettyEmbeddedServletContainerFactory.java

@@ -97,7 +97,8 @@ public class JettyEmbeddedServletContainerFactory extends
 	public EmbeddedServletContainer getEmbeddedServletContainer(
 			ServletContextInitializer... initializers) {
 		WebAppContext context = new WebAppContext();
-		Server server = new Server(new InetSocketAddress(getAddress(), getPort()));
+		int port = getPort() >= 0 ? getPort() : 0;
+		Server server = new Server(new InetSocketAddress(getAddress(), port));
 
 		if (this.resourceLoader != null) {
 			context.setClassLoader(this.resourceLoader.getClassLoader());
@@ -123,7 +124,7 @@ public class JettyEmbeddedServletContainerFactory extends
 		postProcessWebAppContext(context);
 
 		server.setHandler(context);
-		this.logger.info("Server initialized with port: " + getPort());
+		this.logger.info("Server initialized with port: " + port);
 		return getJettyEmbeddedServletContainer(server);
 	}
 
@@ -241,7 +242,7 @@ public class JettyEmbeddedServletContainerFactory extends
 	 * @return a new {@link JettyEmbeddedServletContainer} instance
 	 */
 	protected JettyEmbeddedServletContainer getJettyEmbeddedServletContainer(Server server) {
-		return new JettyEmbeddedServletContainer(server, getPort() > 0);
+		return new JettyEmbeddedServletContainer(server, getPort() >= 0);
 	}
 
 	@Override

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainer.java

@@ -104,6 +104,7 @@ public class TomcatEmbeddedServletContainer implements EmbeddedServletContainer
 		if (connector != null && this.autoStart) {
 			try {
 				connector.getProtocolHandler().start();
+				this.logger.info("Tomcat started on port: " + connector.getLocalPort());
 			}
 			catch (Exception ex) {
 				this.logger.error("Cannot start connector: ", ex);

spring-boot/src/main/java/org/springframework/boot/context/embedded/tomcat/TomcatEmbeddedServletContainerFactory.java

@@ -193,12 +193,8 @@ public class TomcatEmbeddedServletContainerFactory extends
 
 	// Needs to be protected so it can be used by subclasses
 	protected void customizeConnector(Connector connector) {
-		if (getPort() > 0) {
+		int port = getPort() >= 0 ? getPort() : 0;
-			connector.setPort(getPort());
+		connector.setPort(port);
-		}
-		else {
-			connector.setPort(8080);
-		}
 		if (connector.getProtocolHandler() instanceof AbstractProtocol) {
 			if (getAddress() != null) {
 				((AbstractProtocol) connector.getProtocolHandler())
@@ -259,7 +255,7 @@ public class TomcatEmbeddedServletContainerFactory extends
 	 */
 	protected TomcatEmbeddedServletContainer getTomcatEmbeddedServletContainer(
 			Tomcat tomcat) {
-		return new TomcatEmbeddedServletContainer(tomcat, getPort() > 0);
+		return new TomcatEmbeddedServletContainer(tomcat, getPort() >= 0);
 	}
 
 	private File createTempDir(String prefix) {