validators :

If somehow you need to create your own VALIDATION logic to MEET your business needs. You can either create a validation method on the page’s backing BEAN (if you want custom validation for a component on a single page), or create JSF validator classes (if you want to reuse the validation logics by various pages in the application).In the real world, of course creating the custom JSF validator classes would be adopted for ADF application for better reuse and maintantence.

convertors :

converters are used for converting the values from one type to ANOTHER,like decimal to bigdecimal or from string to date or date to string.

validators :

If somehow you need to create your own validation logic to meet your business needs. You can either create a validation method on the page’s backing bean (if you want custom validation for a component on a single page), or create JSF validator classes (if you want to reuse the validation logics by various pages in the application).In the real world, of course creating the custom JSF validator classes would be adopted for ADF application for better reuse and maintantence.

convertors :

converters are used for converting the values from one type to another,like decimal to bigdecimal or from string to date or date to string.