Vasyl Lyashkevych

I think when you correct all the code, you will see exactly your problem places and we can help you

You have more mistakes into the code, for example this:

   public int getCents(){        return new Money(cents);    }

You described that method will return int, but, actually, you try to return Money. So, you need to decide what do you want.
Case 1. Return int.

   public int getCents(){        return this.cents;    }

Case 2. Return Money.

   public Money getCents(){       return new Money(cents);    }

You have two classes with the same name BillMoneyDateDriver. How did you do this?

@Sheriff. Thanks, It was useful for me too!

Yes, it is true, because you wrote:

   public String toString(int sp, int wg) {        return null;    }    public String toString(int sp) {        return null;    }

You need to replace these two methods to single:
   public String toString() {        return "Speed is: " + sp + "\t Weight is:" + wg;    }

At all!

My results look like:
Speed is: 6 Weight is:5 Speed is: 10 Weight is:0

When you return something, that something will be written like:

public String toString() {        return "Speed is: " + this.sp + "\t Weight is:" + this.wg;    }

Because you return "null" like here:

  public String toString(int sp) {        return null;    }

why did you return null? In this case, you don't need this method.

You don't write like:
       System.out.println(obj1.toString(sp));        System.out.println(obj1.toString(wg));

but like:

        System.out.println(obj1.toString());        System.out.println(obj2.toString());
Because in the method :
   public String toString() {        return "Speed is: " + sp + "\t Weight is:" + wg;    }

you need to write how do you present you object into the string for output

I will be more attentive in the future

You created a rectangle but didn't use it:
Rectangle r = new Rectangle(x, y, 40, 60);

Ok, understood

You can define the data into constructors like:

  OverloadedConstructor(int weight, int speed) { // <--- this constructor takes two arguments        this.wg = weight;        this.sp = speed;    }

When you in constructor define the data, later your method toString() can look like:
   public String toString() {        return "Speed is: " + sp + "\t Weight is:" + wg;    }

When you will print your objects like:
System.out.println(obj1.toString());

The results can look like:
Speed is: 6 Weight is:5 Speed is: 10 Weight is:0

For example, you can write apps:
1. Gift recommendation
2. The best price into the shops
3. The closer restaurant
4. The closer park
5. Simple Notebook with reminder
6. Any checker