5. Write a function to return an array containing all elements common to two given arrays containing distinct positive integers. You should not use any inbuilt methods. You are allowed to use any number of arrays. The signature of the function is: int[] f(int[] first, int[] second)

Examples

if input parameters are	return
{1, 8, 3, 2}, {4, 2, 6, 1}	{1, 2}
{1, 8, 3, 2, 6}, {2, 6, 1}	{2, 6, 1}
{1, 3, 7, 9}, {7, 1, 9, 3}	{1, 3, 7, 9}
{1, 2}, {3, 4}	{}
{}, {1, 2, 3}	{}
{1, 2}, {}	{}
{1, 2}, null	null
null, {}	null
null, null	null

by java