question about hashCode in java

Question

public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + id;
return result;
}

can you explan how this code work ,and what is the benefit? ?

Answer 1

I'm not sure about Java but I think it's a unique value representing a unique object, there's 2 ways to define/override it, multiple it by prime numbers or use the id from the relative database:

// written in C#
public override int GetHashCode()
{
return Person?.Id;
}

The benefit of this is that every object will be 99% or completely unique depends on how you override it, you can then store them in a hashset, this increases the performance to search for the object