move custom config example in Java into a code file

akka-docs/general/code/akka/docs/config/ConfigDoc.java

@@ -0,0 +1,30 @@
+/**
+ * Copyright (C) 2009-2012 Typesafe Inc. <http://www.typesafe.com>
+ */
+package akka.docs.config;
+
+public class CustomConfig {
+  public ActorSystem createConfiguredSystem() {
+    //#java-custom-config
+    // make a Config with just your special setting
+    Config myConfig =
+      ConfigFactory.parseString("something=somethingElse");
+    // load the normal config stack (system props,
+    // then application.conf, then reference.conf)
+    Config regularConfig =
+      ConfigFactory.load();
+    // override regular stack with myConfig
+    Config combined =
+      myConfig.withFallback(regularConfig);
+    // put the result in between the overrides
+    // (system props) and defaults again
+    Config complete =
+      ConfigFactory.load(combined);
+    // create ActorSystem
+    ActorSystem system =
+      ActorSystem.create("myname", complete);
+    //#java-custom-config
+    return system;
+  }
+}
+