Иосиф Гудман

String numbers = "6 8 15 7 -8";
String parts[] = numbers.split(" ");
int result[] = new int[parts.length];
for (int i=0; i<parts.length; i++) {
    result[i] = Integer.parseInt(parts[i]);
}
System.out.println(Arrays.toString(result));

String numbers = "6 8 15 7 -8";
int result[] = Arrays.stream(numbers.split(" +")).mapToInt(Integer::parseInt).toArray();