import java.util.Arrays;
class test{

    public static void main(String[] args){

        String[] liste1 = {"Martin Schmidt", "Jürgen Steiner", "Hans Zimmermann", "Robert Dau", "Stefan Simon", "Albert Hesse"};

        String[] liste2 = {"Wolf Schöler", "Cem Kaya", "Jürgen Steiner", "Bernd Bechler", "Martin Schmidt", "Simon Otter", "Robert Dau"};

        String[] liste3 = {"Stefan Simon", "Cem Kaya", "Ulf Richter", "Jürgen Steiner", "Niko Hauser", "Robert Dau"};

        String taeter = Arrays.toString(findSuspects(liste1, liste2, liste3));

        if(findSuspects(liste1, liste2, liste3).length > 0){
            System.out.println("Der/Die Täter ist/sind: " + taeter);
        }
        else{
            System.out.println("Keine Verdächtigen");
        }
    }

    public static String[] findSuspects(String[] a, String[] b, String[] c){

        String[] test = new String[100];
        int zaehler = 0;

        for(int i=0; i < a.length; i++){

            for(int j=0; j < b.length; j++){

                for(int k=0; k < c.length; k++){
                    if(a[i] == b[j] && a[i] == c[k]){
                        test[zaehler] = a[i];
                        zaehler++;
                    }
                }
            }

        }
        String[] tater = new String[zaehler];
        for(int i=0; i<zaehler; i++){
            tater[i] = test[i];
        }

        return tater;
    }

}