doc: Update documentation around java_get, java_set. * NEWS: Don't include java_get, java_set in list of functions deprecated in 3.8. * java.txi: Add java_get, java_set to manual. Write documentation for using '.' operator to read/write fields of object. Add examples of using Java interface. * java_get.m, java_set.m: Change @deftypefn type to "Function File".

#include <octave/oct.h>

DEFUN_DLD (helloworld, args, nargout,
           "Hello World Help String")
{
  int nargin = args.length ();

  octave_stdout << "Hello World has "
                << nargin << " input arguments and "
                << nargout << " output arguments.\n";

  return octave_value_list ();
}