Entity java classes

Small description for the three entity java classes:

In addition to XML files, entity object definitions comprise up to three Java classes:

• The entity object class - an instance of this class (an entity object instance) represents a single row from the datasource
• The entity collection class - an instance of this class represents the collection of rows currently in memory for a single user
• The entity definition class - the singleton instance of this class represents represents the entire datasource object