added play-framework project (#678)

* made changes to java reflection

* removed redundant method makeSound in Animal abstract class

* added project for play-framework article

play-framework/student-api/app/services/Counter.java

@@ -0,0 +1,13 @@
+package services;
+
+/**
+ * This interface demonstrates how to create a component that is injected
+ * into a controller. The interface represents a counter that returns a
+ * incremented number each time it is called.
+ *
+ * The {@link Modules} class binds this interface to the
+ * {@link AtomicCounter} implementation.
+ */
+public interface Counter {
+    int nextCount();
+}