実装例です。
import java.util.Arrays;
import java.util.Random;
public class Q13239285348 {
public static void main(String[] args) {
int[] array = new int[5];
Random r = new Random();
for (int i = 0; i < array.length; i++) {
array[i] = r.nextInt(10) + 1;
}
printArray(array);
int sum = Arrays.stream(array).sum();
System.out.println("合計値：" + sum);
int avg = sum / array.length;
System.out.println("平均値：" + sum / array.length);
System.out.print("平均値より大きい数：");
printArray(Arrays.stream(array).filter(n -> n > avg).toArray());
System.out.print("平均値より小さい数：");
printArray(Arrays.stream(array).filter(n -> n < avg).toArray());
}
private static void printArray(int[] array) {
System.out.println(Arrays.toString(array).replaceAll("\\[|\\]|,", ""));
}
}
