ProcessOptions within AtBeginDocument does not work but ExecuteOptions does

Question

When I have the following class:

\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{CustomClass}
\LoadClass[11pt]{article}
\DeclareOption{option1}{
    \texttt{Text 1}
    \clearpage
    \texttt{Text 2}
    \clearpage
}
\DeclareOption{option2}{
    \texttt{Text 3}
    \clearpage
    \texttt{Text 4}
    \clearpage
}
\AtBeginDocument{
    \ProcessOptions
}
\endinput

And I use it in the following way:

\documentclass[option1]{CustomClass}
\begin{document}
\end{document}

No Pdf is generated. But when I use ExecuteOptions{option1|option2} is work but its static. So my option I specify when specifying the document class does not work.

Why is this happening?

Answer 1

You need to run \ProcessOptions within the class or package file, so it knows which options to process.

\NeedsTeXFormat{LaTeX2e}
\ProvidesClass{CustomClass}
\LoadClass[11pt]{article}
\DeclareOption{option1}{
\AtBeginDocument{%
    \texttt{Text 1}%
    \clearpage
    \texttt{Text 2}%
    \clearpage
}%
}
\DeclareOption{option2}{
\AtBeginDocument{%
    \texttt{Text 3}%
    \clearpage
    \texttt{Text 4}%
    \clearpage
}%
}
\ProcessOptions
\endinput