Added comments and class diagram.

specification/src/main/java/com/iluwatar/app/App.java

@@ -16,7 +16,21 @@ import com.iluwatar.property.Movement;
 import com.iluwatar.selector.ColorSelector;
 import com.iluwatar.selector.MovementSelector;
 
+/**
+ * 
+ * The central idea of Specification pattern is to separate the statement of how to match a candidate, from the
+ * candidate object that it is matched against. As well as its usefulness in selection, it is also valuable for
+ * validation and for building to order.
+ * 
+ * In this example we have a pool of creatures with different properties. We then have defined separate selection
+ * rules (Specifications) that we apply to the collection and as output receive only the creatures that match
+ * the selection criteria.
+ * 
+ * http://martinfowler.com/apsupp/spec.pdf
+ *
+ */
 public class App {
+	
     public static void main( String[] args ) {
     	// initialize creatures list
     	List<Creature> creatures = Arrays.asList(new Goblin(), new Octopus(), new Dragon(), new Shark(), new Troll(), new KillerBee());