Java:

Write a method that returns all elements of the matrix in spiral order in one 1D array. Use 2D arrays as parameters only and not a list.

\begin{tabular}{|l|l|l|l|} \hline 1 & 2 & 3 & 1 \\ \hline 4 & 5 & 6 & 4 \\ \hline 7 & 8 & 9 & 7 \\ \hline 7 & 8 & 9 & 7 \\ \hline \end{tabular}