在Java中，可以使用双向的一对一关联的代码示例如下：

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 street;
    private Person person;

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

    public String getStreet() {
        return street;
    }

    public Person getPerson() {
        return person;
    }

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

public class Main {
    public static void main(String[] args) {
        Person person = new Person("John", new Address("123 Main St."));
        Address address = new Address("456 Elm St.");

        // 设置双向关联
        person.setAddress(address);
        address.setPerson(person);

        System.out.println(person.getName() + " lives at " + person.getAddress().getStreet());
        System.out.println(address.getPerson().getName() + " lives at " + address.getStreet());
    }
}

在这个示例中，Person和Address之间建立了一对一的关联关系。Person类中有一个地址属性，而Address类中有一个人属性。通过设置双向关联，可以轻松地在两个类之间进行导航。