Update 08-observer-strategy.md

notes/08-observer-strategy.md

@@ -90,7 +90,7 @@ The two approaches we have discussed so far are not ideal. The first approach vi
 1. `Observable interface` - This interface defines the methods that the subject class must implement. The subject class is responsible for notifying the observers when the state of the subject changes.
 
 ```java
-public interface class Observable {
+public interface Observable {
     void addObserver(Observer observer);
     void removeObserver(Observer observer);
     void notifyObservers();
@@ -100,7 +100,7 @@ public interface class Observable {
 2. `Observer interface` - This interface defines the methods that the observer class must implement. The observer class is responsible for updating itself when the state of the subject changes.
 
 ```java
-public interface class Observer {
+public interface Observer {
     void notify();
 }
 ```
@@ -279,4 +279,4 @@ To create a strategy object we can also use a factory method.
 * Implementing it in place violates the open-closed principle and makes the code harder to maintain.
 * Inheritance is static, and we cannot change the behavior of the system at runtime.
 * To use the strategy pattern we create a strategy interface and a set of classes that implement it.
-* The context class maintains a reference to a strategy object and delegates the work to it.
+* The context class maintains a reference to a strategy object and delegates the work to it.