The new $system.external interface
The new $system.external interface (aka "InterSystems External Servers") is used to call/integrate with external language code/libraries, it replace the old gateways (for example Java gateway) that required the import of proxy objects.
Note that the documentation for the old gateways has been removed from IRIS, so only the new $system.external interface is somewhat (i.e. insufficiently) documented.
Regarding the migration from old gateway to new $system.external interface the documentation says:
External servers use an enhanced and simplified form of the older Dynamic Object Gateway technology. All Object Gateway features are still available, so upgrading your code is a simple matter of replacing certain class and method references.
Unfortunately that's definitely not the case, apart from very basic code/interface a rewrite of both sides of the interface code (Java and IRIS) is necessary to make it work.
In addition, the promise during the last few years of ISC events (Global Summits) was that you can take advantage of a wide variety of external libraries and consume them directly from IRIS, unfortunately, to do so, more often than not you need to "wrap" the libraries to allow calling them from IRIS.
So, what is reported in the documentation is what the implementation should have been and is not or is just a "bug" in the documentation that is overoptimistic?
What do you think?
If any InterSystems representative is listening, what's your opinion about it?