Why UML is not correct since java code implementation is aggregation?

Question

I have java code which implements aggregation however when UML diagram is generated in IntelliJ Idea, it is generated with a composition symbol (filled diamond).

Code is given below:

public class Address {

    private String city;
    private String state;
    private String country;

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

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getState() {
        return state;
    }

    public void setState(String state) {
        this.state = state;
    }

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    @Override
    public String toString() {
        return "Address{" +
                "city='" + city + '\'' +
                ", state='" + state + '\'' +
                ", country='" + country + '\'' +
                '}';
    }
}

public class Employee {

    private String name;
    private int age;
    private Address address;

    public Employee(String name, int age, Address address) {
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Address getAddress() {
        return address;
    }

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

    @Override
    public String toString() {
        return "Employee{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", address=" + address +
                '}';
    }
}


public class Practice {

    public static void main(String[] args) {

        Address address = new Address("City", "State", "Country");
        Employee employee = new Employee("Name",22, address);


        System.out.println(employee);
        employee = null;
        System.out.println(employee);
        System.out.println(address);
    }
}

When code is run, it meets the requirements of aggregation concept.

My question(s) are:

1. Does not my code implement aggregation correctly?
2. If it implements correctly then why my UML diagram tool detects java code implementation as composition between Employee and Address?

I am looking forward for precise explanation.

Thanks