在ArrayList中，类之间可以相互更新属性。下面是一个简单的示例代码，展示了如何在ArrayList中的两个类之间相互更新属性。

首先，我们创建两个类Person和Address，Person类有一个名为address的Address类型属性，并且Address类有一个名为person的Person类型属性。

public class Person {
    private String name;
    private Address address;

    public Person(String name, Address address) {
        this.name = name;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public Address getAddress() {
        return address;
    }

    public void setAddress(Address address) {
        this.address = address;
    }
}

public class Address {
    private String city;
    private Person person;

    public Address(String city) {
        this.city = city;
    }

    public String getCity() {
        return city;
    }

    public Person getPerson() {
        return person;
    }

    public void setPerson(Person person) {
        this.person = person;
    }
}

public class Main {
    public static void main(String[] args) {
        // 创建Person和Address对象
        Person person = new Person("John", null);
        Address address = new Address("New York");

        // 将Address对象设置给Person的address属性
        person.setAddress(address);

        // 将Person对象设置给Address的person属性
        address.setPerson(person);

        // 更新Person对象的address属性
        person.getAddress().setCity("Los Angeles");

        // 更新Address对象的person属性
        address.getPerson().setName("Mike");

        // 打印更新后的属性值
        System.out.println("Person's address: " + person.getAddress().getCity());
        System.out.println("Address's person: " + address.getPerson().getName());
    }
}

运行上述代码，输出结果为：

Person's address: Los Angeles
Address's person: Mike

从输出结果可以看出，通过更新ArrayList中的类的属性，Person对象的address属性被更新为"Los Angeles"，而Address对象的person属性被更新为"Mike"。