Error calling Java from Ergo

[Rangarajan Krishnamoorthy]

Hi,

I am checking the Ergo to Java interface (I have an evaluation version of Ergo on my Windows machine).

After launching the Ergo IDE, I typed the following command in the Listener:

ensure_loaded @\e2j.

System response:
Times (in seconds): elapsed = 0.000; pure CPU = 0.000

Yes

... done ...

I then entered the following (example given on P23 of "A Guide to ErgoAI Packages" manual):

'123abc789'[message(split(abc)) -> ?P]@\e2j.

System response:
++Error[Ergo]> attempt to call a Prolog predicate in a nonloaded module `ergo_java'

... done ...

What could be the problem?

- Rangarajan

[Rangarajan Krishnamoorthy]

I am sorry the last System response is not clear in my post. It is:

++Error[Ergo]> attempt to call a Prolog predicate in a non-leaded module ‘ergo_java’

… done …

- Rangarajan

[Michael Kifer]

This feature (sending messages to Java) currently works only in the terminal window and not in the IDE.

Very soon we'll release an update that takes care of this problem.

[Rangarajan Krishnamoorthy]

OK, no problem.

I started the terminal mode (executed the batch file "runergo.bat") and then entered the following:

ensure_loaded @\e2j.

This worked.

System[addJar('lispcalls.jar')]@\e2j.

This triggered a warning. I am attaching the screenshot that shows the messages.

What could be wrong this time?

- Rangarajan

[Michael Kifer]

You are probably using Java 9 or 10. In Java 9 they made an incompatible change, which breaks dynamic Jar loading. So, addJar doesn't work in Java 9+ until we find a good solution.

If you need to use a Jar, add it when your Java program starts up (or use Java 8).

--michael