... ClassX is a project aimed at creating an automated system to classify X-ray sources and is envisaged as a prototype of the Virtual Observatory. ... The most fundamental are: (a) classification methods and algorithms, (b) selection and definition of classes (object types), and (c) identification of source counterparts across multi-wavelength data. ... Using different sets of training parameters (attributes), we get different classifiers for the same list of class names (e.g., Figure 1). ...