Isn't this hashCode method self-referential/recursive?

**NimbleSpeaker** · January 26th, 2022, 10:37 AM

I'm learning about overriding equals() and hashCode().
In one of the articles there is this Car class and in it the hashCode() method is being overridden:

@Override
public int hashCode() {
   int result = model == null ? 0 : model.hashCode();
   result = result + manufactureYear;
   result = result + dollarPrice;
   return result;
}

My question is: what happens when the model.hashCode() is called?
It seems to me that it calls the same hashCode() to check if model.hashCode() is equal - so it's recursive.
But apparently it works. So what happens there.

**Norm** · January 26th, 2022, 10:42 AM

Where is the declaration for the class that is referred to by the variable model?
What class is the posted code in?

**NimbleSpeaker** · January 26th, 2022, 10:56 AM

Here's what's in the article:
The Car class:

public class LuxuryAuto {
 
   private String model;
   private int manufactureYear;
   private int dollarPrice;
 
   public LuxuryAuto(String model, int manufactureYear, int dollarPrice) {
       this.model = model;
       this.manufactureYear = manufactureYear;
       this.dollarPrice = dollarPrice;
   }
 
   // ...getters, setters, etc.
}

Then in the main class:

       LuxuryAuto ferrariGTO = new LuxuryAuto("Ferrari 250 GTO", 1963, 70000000);
       LuxuryAuto ferrariSpider = new LuxuryAuto("Ferrari 335 S Spider Scaglietti", 1963, 70000000);
 
       System.out.println("What are their hash codes?");
       System.out.println(ferrariGTO.hashCode());
       System.out.println(ferrariSpider.hashCode());

**Norm** · January 26th, 2022, 11:17 AM

Ok so model is a String. It has its own hashCode method.

What class is your hashCode method in? It obviously is not in a class that extends String.
So how is there any conflict? Where is the recursion?
What is your confusion?

**NimbleSpeaker** · January 26th, 2022, 11:34 AM

Oh, God. Now I get, it clicked!
So, it calls the String class's hashCode().
But if I don't override the method in the LuxuryAuto class and call the method:
System.out.println(ferrariGTO.hashCode());

Will it call Object class's hashCode() method?

Thanks, man!

**Norm** · January 26th, 2022, 11:40 AM

it call Object class's hashCode() method

Yes

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