Thread populating collection and Java memory model

I noticed that If I let a thread populate a collection, at the end of the thread after the join, I see the collection populated as expected.

In respect to the Java memory model, is this always guaranteed to happen ?

what if the thread is storing the references of the objects in the list in the cpu cache ?
In this case after the join the joining thread would have to guarantee to see the changes ?

final ArrayList<Person> persons = new ArrayList();
Thread myThread = new MyThread(persons);
myThread.start();
myThread.join();

// persons ?

Thread

public class MyThread extends Thread {
    
    ArrayList<Person> persons;

    public MyThread(ArrayList<Person> persons){
     this.persons = persons;
    }

    public void run(){
      persons.add(new Person(...))
      // add more
    }
  }