QED symbol in latex

It seems to me that what you really want, is to customize the look of the captions. This is most easily done using the caption package. For instructions how to use this package, see the manual (PDF). You would probably need to create your own custom caption format, as described in chapter 4 in the manual.

Edit: Tested with MikTex:

\documentclass{report}

\usepackage{color}
\usepackage{xcolor}
\usepackage{listings}

\usepackage{caption}
\DeclareCaptionFont{white}{\color{white}}
\DeclareCaptionFormat{listing}{\colorbox{gray}{\parbox{\textwidth}{#1#2#3}}}
\captionsetup[lstlisting]{format=listing,labelfont=white,textfont=white}

% This concludes the preamble

\begin{document}

\begin{lstlisting}[label=some-code,caption=Some Code]
public void here() {
    goes().the().code()
}
\end{lstlisting}

\end{document}

Result:

Use p{width} for your column specifiers instead of l/r/c.

\begin{tabular}{|p{1cm}|p{3cm}|}
  This text will be wrapped & Some more text \\
\end{tabular}

EDIT: (based on the comments)

\begin{table}[ht]
    \centering
    \begin{tabular}{p{0.35\linewidth} | p{0.6\linewidth}}
      Column 1  & Column2 \\ \hline
      This text will be wrapped & Some more text \\
      Some text here & This text maybe wrapped here if its tooooo long \\
    \end{tabular}
    \caption{Caption}
    \label{tab:my_label}
\end{table}

we get: