Prevent NPE error in Pojo's with synthetic properties

JAVA-3915

Author: rozza

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

@@ -166,6 +166,8 @@ private static <T, S> PropertyMetadata<T> getOrCreateMethodPropertyMetadata(fina
     }
 
     private static boolean isAssignableClass(final Class<?> propertyTypeClass, final Class<?> typeDataClass) {
+        notNull("propertyTypeClass", propertyTypeClass);
+        notNull("typeDataClass", typeDataClass);
         return propertyTypeClass.isAssignableFrom(typeDataClass) || typeDataClass.isAssignableFrom(propertyTypeClass);
     }