src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/parser/JSONParser.java

*** 248,265 ****
          final PropertyMap newMap;
          final Class<?> type = ObjectClassGenerator.OBJECT_FIELDS_ONLY ? Object.class : getType(value);
  
          if (oldProperty != null) {
              values.set(oldProperty.getSlot(), value);
!             newProperty = new SpillProperty(id, 0, oldProperty.getSlot());
!             newProperty.setType(type);
!             newMap = propertyMap.replaceProperty(oldProperty, newProperty);;
          } else {
              values.add(value);
!             newProperty = new SpillProperty(id, 0, propertyMap.size());
!             newProperty.setType(type);
!             newMap = propertyMap.addProperty(newProperty);
          }
  
          return newMap;
      }
  
--- 248,261 ----
          final PropertyMap newMap;
          final Class<?> type = ObjectClassGenerator.OBJECT_FIELDS_ONLY ? Object.class : getType(value);
  
          if (oldProperty != null) {
              values.set(oldProperty.getSlot(), value);
!             newMap = propertyMap.replaceProperty(oldProperty, new SpillProperty(id, 0, oldProperty.getSlot(), type));;
          } else {
              values.add(value);
!             newMap = propertyMap.addProperty(new SpillProperty(id, 0, propertyMap.size(), type));
          }
  
          return newMap;
      }