We develop a static method, `maxArray()`, which takes as parameter an
array of integers and returns the maximum value in the array. We assume that
the array contains at least one element. A possible realization is the
following:

public static long maxArray(long[] v) { long max = v[0]; for (int i = 1; i < v.length; i++) if (v[i] > max) max = v[i]; return max; }

Notice that the method uses a variable `max` to hold the current maximum
while iterating over the elements of the array. The variable `max` is
initialized to the value of the first element of the array, which by assumption
must exist. Then `max` is updated whenever a bigger element is found.
Hence, at the end of the loop, the value of `max` will coincide with the
value of the maximum element of the array, and such a value is returned.

*Example of usage:*

public static void main(String[] args){ long[] x = { 42, 97, 31, -25 }; // creation of an array x of 4 long System.out.println(maxArray(x)); // prints out 97 }