Simple expression throws “Undefined control sequence”

Question

I have a simple expression in my text which refuses to compile and I don't know why:

...\textit{isInterestedIn(Class$\<$? extends ContentChange$\>$ changeClass)}...

The complete error statement goes like this:

! Undefined control sequence.
<recently read> \<
l.298 ...? extends ContentChange$\>$ changeClass)}
mit einem der \textit{Tex...
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

I don't really understand, what's the problem here.

Answer 1

The command (called control sequence) \< is unknown. \ means the start of a control sequence. Write $<$ or $\backslash<$ instead, the latter if you really need a backslash .

Answer 2

You do not need to use math mode to get text < and >. A simpler solution is to either use T1 font encoding, or an opentype font (with lualatex or xetex). For example, with pdflatex

\documentclass{article}
\usepackage[T1]{fontenc}
\begin{document}
\textit{<text>}
\end{document}

or with lualatex

\documentclass{article}
\usepackage{fontenc}
\setmainfont{TeX Gyre Pagella}
\begin{document}
\textit{<text>}
\end{document}