Drools now has complete runtime support for DMN (Decision Model and Notation). DMN files are now an asset that can be added to any kjar for execution.
My thinking here is that Drools Rule is a non standard/proprietary where as DMN is open but newer standard.
My question..
Are Drools Rules (.drl files) and DMN (.dmn) addressing the same problem? Does DMN intend to replace DRL in the long run?
Drools Rule is a non standard/proprietary
This is incorrect, DRL is not proprietary; Drools.org license is Apache Software License hence Open Source. The DRL format is defined as per DRL grammar, code and documentation of the Drools.org project.
Are Drools Rules (.drl files) and DMN (.dmn) addressing the same problem?
There are some overlaps, but their aims are different.
DRL is a technical rule language, also enables CEP (Complex Event Processing), forward-backward chaining rule style of application etc. With DRL also you can describe both stateless or stateful rule base. Being a technical language, it is often used in conjunction with guided rules, DSLs, guided decision table in order to be even more accessible also for business analyst.
DMN is a standard and visual notation for Decision Management, aiming to bridge the gap between technical and business analysis, with a defined execution semantics by the standard specification itself. In comparison to DRL it might complement as a valid additional tool. For instance the decision logic expressed with DMN is stateless; a more complex application could see a stateful application being comprised of DRL rules, DMN evaluations, CEP style etc. It depends on the use-case.
Does DMN intend to replace DRL in the long run?
As described above there might be few overlaps, but their aims are different; the intent is not a "replacement", instead they are complementary tools.
Disclaimer: I am a contributor to the drools.org project and to the DMN TCK project.