Java interface: starting point

[Ernst Reissner]

I think a good starting point is:

bug #48820: Java interface: documentation of type conversions Java<=>Octave

Matlab provides extensive documentation on that feature,
which is appropriate since it is really complex.

We should also add a seperate section in the manual describing the features.
At the same time, this feature is the startpoint motivating many feature requests and bug reports.

Greetings,

Ernst