Find All Solutions for the System $\left\{ \begin{array} { l } x y = 4 \\x ^ { 2 } + y ^ { 2 } = 8\end{array} \right.$

Find all solutions for the system. $\left\{ \begin{array} { l } x y = 4 \\x ^ { 2 } + y ^ { 2 } = 8\end{array} \right.$