diff --git a/observer/src/main/java/com/iluwatar/App.java b/observer/src/main/java/com/iluwatar/App.java
index 9f59473d5..a128fd38f 100644
--- a/observer/src/main/java/com/iluwatar/App.java
+++ b/observer/src/main/java/com/iluwatar/App.java
@@ -1,5 +1,12 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Observer pattern defines one-to-many relationship
+ * between objects. The target object sends change
+ * notifications to its registered observers.
+ *
+ */
 public class App 
 {
     public static void main( String[] args )
diff --git a/observer/src/main/java/com/iluwatar/Weather.java b/observer/src/main/java/com/iluwatar/Weather.java
index cc43fa6c7..f3c11ac73 100644
--- a/observer/src/main/java/com/iluwatar/Weather.java
+++ b/observer/src/main/java/com/iluwatar/Weather.java
@@ -3,6 +3,12 @@ package com.iluwatar;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * 
+ * Weather can be observed by implementing WeatherObserver
+ * interface and registering as listener.
+ *
+ */
 public class Weather {
 
 	private WeatherType currentWeather;
diff --git a/observer/src/main/java/com/iluwatar/WeatherObserver.java b/observer/src/main/java/com/iluwatar/WeatherObserver.java
index ac4e1c8a5..6af020240 100644
--- a/observer/src/main/java/com/iluwatar/WeatherObserver.java
+++ b/observer/src/main/java/com/iluwatar/WeatherObserver.java
@@ -1,5 +1,10 @@
 package com.iluwatar;
 
+/**
+ * 
+ * Observer interface.
+ *
+ */
 public interface WeatherObserver {
 
 	void update(WeatherType currentWeather);