All of the classes related to the UI Component Validation Service are packaged in com.ptc.core.ui.validation. Their source is located in the module \Windchill\src\com\ptc\core\ui\validation. It is strongly recommended that any time a developer is doing Validator development, they update all of the files in this directory and compile the latest versions of the Java classes.

Developers writing Validators should put their Validator classes in a package or module that is meaningful for the action(s)/UI component(s) that the Validator validates.