hashCode()

If an implementation is not provided, the compiler will generate a hashCode() method that considers all primary constructor properties in its comparison. The following code shows the hashCode() implementation of our Article class example:

public final class Article {
   ...

   public int hashCode() {
      String var10000 = this.title;
      int var1 = (var10000 != null ? var10000.hashCode() : 0) * 31;
      String var10001 = this.author;
      return var1 + (var10001 != null ? var10001.hashCode() : 0);
   }
}

Once again, we can see that the implementation only takes into account primary constructor properties in its implementation of hashCode().