Comparative table with vertical text in first row and column

I'm quite new to LaTeX and I would like to create a comparative table where the first row AND the first column of the table are written vertically. I tried several solutions I found on stackexchange with "multicolumn" and "rotate" but none was a success (e.g. the text doesn't appear or it is written horizontally).

I succeeded to create a table with the expected colors via a thread I found here.

The result I wish is the following :

The result I have currently :

Code :

\documentclass[11pt]{article}

\usepackage[dvipsnames]{xcolor}
\usepackage{tabu}
\usepackage{colortbl}
\usepackage{array,multirow,graphicx}

\begin{document}

\taburowcolors[2]{white .. black!20}
\tabulinesep=4pt
\begin{tabu}{|>{\cellcolor{black!60}\color{white}}r|X[cm]|X[cm]|}
\hline
\rowcolor{black!80}\cellcolor{black!80}Java & \color{white}Open source& \color{white}\# operators \\
Tool1 & Yes & 1\\
Tool2 & Yes & 2\\
Tool3 & Yes & 3\\
\rowcolor{black!80}\cellcolor{black!80}C/C++ & ~ & ~ \\
Tool1 & Yes & 1\\
Tool2 & No & 2\\
Tool3 & Yes & 3\\
\rowcolor{black!80}\cellcolor{black!80}Python& ~  & ~ \\
Tool1 & No & 1\\
Tool2 & Yes & 2\\
Tool3 & Yes & 3\\
\hline
\end{tabu}

\end{document}

• welcome to tex.se! please extend your code snippet to complete small document (beginning with \documentclass and ending with \end{document) with this table. – Zarko Dec 10 '18 at 16:57

like this?

\documentclass{article}
\usepackage[table]{xcolor}
\usepackage{graphicx}
\usepackage{multirow, tabu}

\begin{document}
\taburowcolors[2]{white .. black!20}
\tabulinesep=4pt
\begin{tabu}{>{\columncolor{black!80}\color{white}}c r |
c | c
!{\vrule width 0.5pt}@{}
!{\color{black!80}\vrule width 1ex}
}
\rowcolor{black!80}
&  \multicolumn{1}{c!{\color{white}\vline}}{}
& \multicolumn{1}{c!{\color{white}\vline}}{%
\rotatebox{90}{\textcolor{white}{Open source}}}
& \multicolumn{1}{c!{\color{white}\vline}@{}
!{\color{black!80}\vrule width 1ex}}{%
\rotatebox{90}{\textcolor{white}{\# operators}}}    \\
\hline
\cellcolor{black!80}
& \cellcolor{black!40}{Tool1}
& Yes   & 1 \\
\cellcolor{black!80}
& \cellcolor{black!40}{Tool2}
& Yes   & 2 \\
\cellcolor{black!80}
\multirow{-3}{*}[-1ex]{\rotatebox{90}{Java}}
&  \cellcolor{black!40}{Tool3}
& Yes   & 3 \\
\rowcolor{black!80}
&       &       &   \\
\hline
\end{tabu}
\end{document}

• Thank you very much, your solution solves my problem :) – Vincent Passau Dec 10 '18 at 18:43