A program that outputs a number greater than or equal to the input integer and a number less than the input integer from an array with 50 elements.

I am currently studying java and am doing the task of creating the title program. I want to randomly create an array with 50 elements, then output a number greater than or equal to the input integer, and then start a new line and output a number less than the input integer, but that doesn't work. Can you give me some advice on where to fix it?

class test17 {
    public static void main(String[] args) {
        int[] array = PConsole.createRandomIntArray(1, 300, 50, true);
        int th= PConsole.inputIntNum(1, 300); //Threshold

        int upper = array[0];
        int lower = array[1];

        for (int i = 0; i < array.length; i++) {
            if ( array[i]>= th) {
              upper+= array[i]+" ";
            }else{
              lower+= array[i]+" ";
            }
        }
        System.out.println(th);
        System.out.println(upper);
        System.out.println(lower);
    }
}