Replace explicit type arguments with diamond operator

samples/javaconfig/rest/src/main/java/sample/mvc/RestDemoController.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2016 the original author or authors.
+ * Copyright 2014-2017 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.
@@ -35,7 +35,7 @@ public class RestDemoController {
 
 	@RequestMapping(value = "/", produces = "application/json")
 	public Map<String, String> helloUser(Principal principal) {
-		HashMap<String, String> result = new HashMap<String, String>();
+		HashMap<String, String> result = new HashMap<>();
 		result.put("username", principal.getName());
 		return result;
 	}