\begin{tikzpicture}
\umlemptyclass{A}
\umlemptyclass[x=5, y=2]{B}
\umluniassoc[name=assoc, geometry=-|]{A}{B}
\draw (assoc-1) node[fill=black, circle, inner sep=0.1cm] {} node[above=0.2cm] {relname-1};
\draw (assoc-2) node[fill=black, circle, inner sep=0.1cm] {} node[right=0.2cm] {relname-2};
\draw (assoc-3) node[fill=black, circle, inner sep=0.1cm] {} node[right=0.2cm] {relname-3};
\end{tikzpicture}