Captain is implementing RowingBoat - Adapter pattern

Captain and RowingBoat aren't interchangable. 
Captain, as a client, may have a method to use the boat, but it isn't needed that they share the same interface, as it makes the code more confusing.

adapter/src/main/java/com/iluwatar/adapter/Captain.java

@@ -26,7 +26,7 @@ package com.iluwatar.adapter;
  * The Captain uses {@link RowingBoat} to sail. <br>
  * This is the client in the pattern.
  */
-public class Captain implements RowingBoat {
+public class Captain {
 
   private RowingBoat rowingBoat;