I need to write Method with the following headers in Java.

Write methods with the following headers Part 1 public static int twoSum(int[] arr) - returns the number of pairs of unique values whose sum equals zero. Assume that the input array is sorted in ascending order and the values stored in the array are unique. Example: If arr (-13, -9, -2, 0, 1, 2, 4, 9, 11) then there are two pairs whose sum is zero. (-9 +9 0 and -2 +2 0). Each array element can be inspected at most one time. Therefore, you cannot use a nested loop. Stop iterating once the method determines there are no more remaining pairs that sum to zero. Hint: Set an int variable called numPairs to 0. Set an int variable called left to 0 and an int variable called right to arr.length - 1. Iterate if (i) left