Tex code snippet problem

code_snippet.tex

% Glider, a hacker emblem (http://www.catb.org/hacker-emblem/)
% Author: Alex Hirzel
% License: Public Domain
\documentclass[border=1mm]{article}
\usepackage{tikz}
%%%<
\usepackage{verbatim}
\usepackage{listings}

\begin{document}

\def\codefont{
%\fontspec{Courier New}
  \fontsize{9pt}{11pt}\selectfont}
\definecolor{codebgcolor}{HTML}{EDEDED}
\newenvironment{code}
{\begin{center}
    \begin{tikzpicture}
      \node [fill=codebgcolor,rounded corners=5pt]
      \bgroup
      \bgroup\codefont
      \begin{tabular}{l}}
      {\end{tabular}
      \egroup
      \egroup;
    \end{tikzpicture}
  \end{center}}

\section{Explaining using Code Snippets}
This particular Latex document makes use of code snippets to explain the concepts.
Here is our hello world program in Java.

\begin{code}
\begin{lstlisting}
public class HelloWorld {
  public static void main(String[] args) {
    /* ... more code ... */
  }
}
\end{lstlisting}
\end{code}

\end{document}

Credit: http://randomlogs.wordpress.com/2010/02/06/