=clu #18345 Support local address in cluster commands

* and clarify the doc sample for leave

akka-docs/rst/java/code/docs/cluster/ClusterDocTest.java

@@ -0,0 +1,41 @@
+/**
+ * Copyright (C) 2015 Typesafe Inc. <http://www.typesafe.com>
+ */
+package docs.cluster;
+
+import com.typesafe.config.ConfigFactory;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import akka.actor.ActorSystem;
+import akka.cluster.Cluster;
+import akka.testkit.JavaTestKit;
+
+
+public class ClusterDocTest {
+  
+  static ActorSystem system;
+  
+  @BeforeClass
+  public static void setup() {
+    system = ActorSystem.create("ClusterDocTest", 
+        ConfigFactory.parseString(ClusterDocSpec.config()));
+  }
+
+  @AfterClass
+  public static void tearDown() {
+    JavaTestKit.shutdownActorSystem(system);
+    system = null;
+  }
+
+  @Test
+  public void demonstrateLeave() {
+    //#leave
+    final Cluster cluster = Cluster.get(system);
+    cluster.leave(cluster.selfAddress());
+    //#leave
+
+  }
+
+}