test.tex

\documentclass{jsarticle}
\usepackage{listings, jlisting}
\begin{document}

%% OK
\begin{lstlisting}[caption=test1,language={ruby}]
class Foo
end
\end{lstlisting}

%% ???
\begin{lstlisting}[title=test2,language={ruby}]
class Foo
end
\end{lstlisting}

\end{document}