Runtimes, like in cloud, may only know component-api in which there is component runtime.

It happens that error message are not well displayed when the ComponentException has a cause with a subclass of Exception that is unknown by the final application.

A way to prevent such issue would be to recursively transform all cause exceptions to a low level Exception class.

[EDIT]

Some more explanations:

To sumarize:

• Applications that use TCK, like pipeline designer or studio, run pipeline with connectors.
• Connectors  have their own class loader
  • For instance my JiraInput could use a JiraJavaLib (just an example not the reality)
    • The JiraJavaLib contains JiraException
  • It can happen that my connector raise an Exception and the the exception is a JiraException instance
• Since connectors are isolated with their own class loader, the runtime applictation (studio or pipeline designer) doesn't know about JiraException
  • So when it receiver this exception it fails with a ClassNotFoundException
  • It's more true for pipeline designer since exception is first serialized and the ClassNotFoundException is raised when it tries to deserialize the Exception

That's why we ask that TCK connectors!

• only raise ComponentException
  • It is known by runtime application since it is part of the TCK API
• Connector must not inherit from that class
  • runtime application will not know those sub-classes

But, there is still an issue:

• ComponentException can have a 'cause' exception, and that cause can have also a 'cause', etc...
• We are facing the same issue:
  • Cause classes MUST be known by runtime applications
    • if not, it could throw a ClassNotFoundException

This ticket is about to re-recreate the 'cause' chain but with 'standard' Excpetion from java.lang: Exception or Throwable.
Example:

• For instance my connector could raise:

  ComponentEception --cause--> JiraException --cause-->JiraTimeoutException --cause-->CommonApacheNetException

  • the runtime application may not know JiraException, JiraTimeoutException, CommonApacheNetException classes
• it should be translated to :  

  ComponentEception --cause--> Exception --cause-->Exception --cause-->Exception

  • All causes are instances of Exception, not instance of subclasses of Exception that's the differnce, all runtime applicaiton know about Exception class
  • We should convert specific JiraException, JiraTimeoutException, CommonApacheNetException exception to generic Exception copying message and stacktrace into them.

[EDIT]
I think some unit tests should be enough to check if all the causes chain are transformed to Exception instances