The listing package allow you to insert code from an external file.
See the official documentation for more information.
Or copy paste the example below.
You can also write code directly in your .tex file.
\documentclass[11pt]{article}
\usepackage{listings}
%those are just lines to make it look nice
\lstset{frame=tb,
language=Java,
aboveskip=3mm,
belowskip=3mm,
showstringspaces=false,
columns=flexible,
basicstyle={\small\ttfamily},
numbers=none,
numberstyle=\tiny\color{gray},
keywordstyle=\color{blue},
commentstyle=\color{dkgreen},
stringstyle=\color{mauve},
breaklines=true,
breakatwhitespace=true
tabsize=3
}
\usepackage{color} %this is to add some cool colors
\definecolor{dkgreen}{rgb}{0,0.6,0}
\definecolor{gray}{rgb}{0.5,0.5,0.5}
\definecolor{mauve}{rgb}{0.58,0,0.82}
\begin{document}
\lstinputlisting[language=java, inputencoding=utf8]{getParent.java}
\end{document}
