Simplistic Organization

Organization.java

import java.util.ArrayList;

public class Organization {

    String name;
    String address;
    
    ArrayList<Person> persons = new ArrayList<>();
    ArrayList<Department> departments = new ArrayList<>();
}

class Person {

    String id;
    String name;
    String address;
    String mobileNumber;
    String email;
    String salary;
}

class Department {

    String name;
    String id;

    ArrayList<Person> personnel = new ArrayList<>();
}

OrganizationTest.java

import static java.lang.System.out;

public class OrganizationTest {

    public static void main(String[] args) {
        Organization org = new Organization();
        
        org.name = "Organization, Inc.";
        org.address = "1234 Drifting ln";
        
        Person person = new Person();
        
        person.name = "Person's Name";
        person.email = "user@example.com";
        
        Department dept = new Department();
        
        dept.name = "Department A";
        
        org.departments.add(dept);
        org.persons.add(person);
        
        out.println("org name: "+ org.name);
        out.println("address: "+ org.address);
        out.println("person name: "+ person.name);
        out.println("person email: "+ person.email);
        out.println("dept name: "+ dept.name);
        for (Department d : org.departments)
            System.out.println("dept name: "+ d.name)
            ;
        for (Person p : org.persons)
            System.out.println("person name: "+ p.name)
            ;            
        
        Person manager = new Person();
        manager.name = "Paul";
        dept.personnel.add(manager);
        
        dept.personnel.add(person);
        
        for (Person p : dept.personnel)
            out.println("dept personnel: "+ p.name)
            ;
    }
}