code: public Class getPropertyType(String propertyPath) {
  
          if (propertyPath == null) {
              throw new IllegalArgumentException("Propertyname may not be null");
          }
  
          StringTokenizer tokenizer = new StringTokenizer(propertyPath, ".", false);
          return getPropertyType(tokenizer);
      }
docs: Retrieves the type of the given property path.
  
  @param propertyPath The dot-separated path of the property type to retrieve. E.g. directly property: "name",
  sub property: "streetAddress.number"
  @return the type of the property with the given name or null if the propertyName is not a property of the class managed
  by this reader.
  @throws IllegalArgumentException if propertyName is null.