cdm/src/main/java/uk/ac/rdg/resc/edal/time/FixedYearVariableMonthChronology.java
private static int sumArray(int[] arr) {
        if (arr == null) throw new NullPointerException("null array");
        if (arr.length == 0) throw new IllegalArgumentException("Zero-length array");
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] <= 0) {
                throw new IllegalArgumentException("All array values must be > 0");
            }
            sum += arr[i];
        }
        return sum;
    }
private static int sumArray(int[] arr) {
        if (arr == null) throw new NullPointerException("null array");
        if (arr.length == 0) throw new IllegalArgumentException("Zero-length array");
        int sum = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] <= 0) {
                throw new IllegalArgumentException("All array values must be > 0");
            }
            sum += arr[i];
        }
        return sum;
    }
Calculates the sum of the values in the given array.
@throws NullPointerException if arr is null
@throws IllegalArgumentException if arr is empty or contains
zero or negative values.