Реализовать метод

import java.util.Random;
import java.util.stream.Stream;
 
public class Helper {
 
    public static void main(String[] args) {
        Random random = new Random();
        Stream.generate(() -> depGenerator(random.nextInt(14)))
                .limit(15).forEach(System.out::println);
    }
 
    private static Deposit depGenerator(int aNumber) {
        return aNumber % 2 == 0 ? new SpecialDeposit("Sp", aNumber) :
                new LongDeposit("Ld", aNumber);
    }
}
abstract class Deposit {
    private String ownerName;
    private int summa;
 
    public Deposit(String ownerName, int summa) {
        this.ownerName = ownerName;
        this.summa = summa;
    }
 
    public boolean isProlong() { return true;}
 
    public String getOwnerName() {
        return ownerName;
    }
 
    public int getSumma() {
        return summa;
    }
 
    @Override
    public String toString() {
        return this.ownerName + " - " + this.isProlong();
    }
}
//###
class SpecialDeposit extends Deposit {
    private int limitProlong = 8;
 
    public SpecialDeposit(String ownerName, int summa) {
        super(ownerName, summa);
    }
 
    @Override
    public boolean isProlong() { return super.getSumma() > limitProlong;}
}
//###
class LongDeposit extends Deposit {
    private int limitProlong = 4;
 
    public LongDeposit(String ownerName, int summa) {
        super(ownerName, summa);
    }
 
    @Override
    public boolean isProlong() { return super.getSumma() > limitProlong;}
}