programming language is JAVA:

The sum of the elements of an integer -valued array recursively calculated as follows:

The sum of an array of size 0 is 0;

Otherwise, the sum of the first n elements of an array is the sum of the last of these added to the sum of the previous n-1 elements .

Write an int method named sum that accepts an integer array , and the number of elements in the array and returns the sum of the elements of the array .