Importers method do not support null object for DataSource, Path, InputStream, etc.

[miovd]

• Do you want to request a feature or report a bug? Bug

• What is the current behavior? Null objects in Importers method are processed without any throwed exception.

• If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem This has been discussed here. There are tests that show this behavior.

• What is the expected behavior? An exception should be thrown: objects should be required not null.

• What is the motivation / use case for changing the behavior? Preventing NPE along the way