Fixed issue BruceEckel#46

Author: BruceEckel

generics/Diamond.java

@@ -3,11 +3,9 @@
 // We make no guarantees that this code is fit for any purpose.
 // Visit http://OnJava8.com for more book information.
 
-class Bob {}
-
 public class Diamond<T> {
   public static void main(String[] args) {
-    GenericHolder<Bob> h3 = new GenericHolder<>();
-    h3.set(new Bob());
+    GenericHolder<Automobile> h3 =
+      new GenericHolder<>();
   }
 }

generics/GenericHolder.java

@@ -10,7 +10,7 @@ public GenericHolder() {}
   public T get() { return a; }
   public static void main(String[] args) {
     GenericHolder<Automobile> h3 =
-      new GenericHolder<>();
+      new GenericHolder<Automobile>();
     h3.set(new Automobile()); // type checked
     Automobile a = h3.get(); // No cast needed
     //- h3.set("Not an Automobile"); // Error