Use java stream api

use this method signature

What number spent the longest time on the phone? Return the correct number as a string.

public class LongestCall { public String solution() { //  your code goes here  return ""; } }

below is the "calls.csv" file

94116 05877,(0731)4702212,01-09-2016 18:17:28,507 98448 87878,90366 46573,01-09-2016 18:19:21,517 (080)45547058,84319 52539,01-09-2016 18:16:28,964

Note: duration of the call is the last column, for example: 507, 517, 964