\begin{tikzpicture}
\umlemptyclass{A}
\umlemptyclass[x=6, y=-3]{B}

\umlHVassoc[name=assoc, attr=t|*, pos=1.9]{A}{B}
\umlassocclass[geometry=|-|,x=2, y=-3]{C}{assoc-1}{}{}
\end{tikzpicture}