I'm having a strange problem with listings. I'm trying to use matching double quotes around strings, as in this minimal example:

```
\documentclass{article}

\usepackage{listings}
\lstset{
    language=Java,
    tabsize=2,
    numbers=left,
    basicstyle=\footnotesize
}

\begin{document}

\begin{lstlisting}
void my_method() {
    int test = 0;
    some_method(``string");
    boolean b = false;
    some_method(``string");

}
\end{lstlisting}

\end{document}

```

First of all, the backticks render individually instead of as a nice curly left double quote like I want. And, well, the bigger problem is that after inserting the backticks it starts showing all the whitespace in my code in between the two strings, even when I add showspaces=false to my settings, as in the following screenshot:

[![result of the above markup](https://i.stack.imgur.com/gegrz.png)](https://i.stack.imgur.com/gegrz.png)

I've found a lot about how to use straight double quotes, but I actually do want the curly quotes. Does anyone know how I can insert the left quotation marks properly?