Custom error handling triggering options

What are the options for triggering a custom error handler in a microflow? When a microflow triggers a validation rule error I know that then the custom error handler can be triggered. But I would like to know if there are other options, maybe via a validation feedback message? Or does a validation feedback message not trigger an error that can be handler by the error handler?
2 answers

In many of my projects, i create a java actions which just throws an exception (of my own custom exception class, usually with a single string argument (message)), to trigger custom exception handling.

Validation feedback does not trigger an exception. Even more important, you will notice validation feedback only if the microflow is called by a form, not when its called by a webservice.


Performing any "illegal" operation will trigger an error handler. Ie, the following microflow expression would trigger an error handler:


I'm sure there are other ways, I don't have an extensive list handy. Basically, anything that will cause java to throw an exception will also trigger an error handler in microflows.