No, XDP cannot be edited in AEM.

This is the wrong forum for this question. This question is related to Acrobat Document Cloud APIs and should be posted in forums for Acrobat DC. 

You are facing a NPE because the Junit test you are writing is a basic unit test with no server-side integration and hence, the instance of AssemblerService will always be null. What you need to write is an integration test using Apache Sling Teleporter framework which will help you write the test l...

I have observed that - in the custom LogVariable step, the document variable is converted to String since the default value supplied to metadataMap.get() is a String.This conversion of the document to String is not recommended since the workflow engine tries to convert it to JCR Value and then the J...