Made Map and Collection codecs final

Author: rozza

bson/src/main/org/bson/codecs/pojo/CollectionCodec.java

@@ -27,7 +27,7 @@
 import java.util.Collection;
 
 
-class CollectionCodec<T> implements Codec<Collection<T>> {
+final class CollectionCodec<T> implements Codec<Collection<T>> {
     private final Class<Collection<T>> encoderClass;
     private final Codec<T> codec;
 

bson/src/main/org/bson/codecs/pojo/MapCodec.java

@@ -28,7 +28,7 @@
 import java.util.Map.Entry;
 
 @SuppressWarnings({"unchecked", "rawtypes"})
-class MapCodec<T> implements Codec<Map<String, T>> {
+final class MapCodec<T> implements Codec<Map<String, T>> {
     private final Class<Map<String, T>> encoderClass;
     private final Codec<T> codec;