import java.util.HashSet;

import java.util.Scanner;

import java.util.Set;

public class PrimeNumbersFilter {

public static void main(String[] args) throws P1Exception {
    int numberCount = new Scanner(System.in).nextInt();
    int[] primeNumbers = filterPrimeNumbers(generate(numberCount));
    for (int primeNumber : primeNumbers) System.out.print(primeNumber + " ");
}

public static int[] generate(int numberCount) throws P1Exception {
    if (numberCount <= 0) throw new P1Exception();
    int[] numbers = new int[numberCount];
    for (int i = 0; i < numbers.length; i++) numbers[i] = (int) (Math.random() * (1000) + 1);
    return numbers;
}

public static int[] filterPrimeNumbers(int[] numbers) throws P1Exception {
    Set<Integer> primeNumbers = new HashSet<>();
    for (int number : numbers) {
        if (isPrime(number))
            primeNumbers.add(number);
    }
    int[] primeNumbersArray = new int[primeNumbers.size()];
    int i = 0;
    for (int primeNumber : primeNumbers) {
        primeNumbersArray[i] = primeNumber;
        i++;
    }
    return primeNumbersArray;
}

private static boolean isPrime(int number) throws P1Exception {
    if (number < 0) throw new P1Exception();
    boolean isPrime = true;
    for (int i = 2; i < number / 2; i++) {
        if (number % i == 0) {
            isPrime = false;
            break;
        }
    }
    return isPrime;
}

static class P1Exception extends Exception {

    public P1Exception() {
        System.err.println("Invalid number.");
    }
}

}

Bei der Erzeugung der zufälligen Zahlen, musst du die Implementierung so ändern, wie sie gewünscht ist, also das Muster mit den Lottozahlen aus der Vorlesung (siehe Aufgabentext)