Returns null when calling method in another class

Question

Very simple question but very little luck.

My problem is that when I attempt to call on get methods getUserID and getPassword of class User in class Login , I get null.

I have looked at other posts with a similar problem to mine. Although I found few posts to guide me, a common issue was that the poster had not initialised the class object but I have done that.

I need specific code here because I've tried a lot of things but can't get it to work. I hope that I provided enough info to help you assist me.

User class

public class User 
{
private String userID;
private String password;
private Employee employee;
private String authorityLevel;
/**
 * Constructor for User class - Initialise a fixed password and employee object.
 */
public User()
{  
    employee = new Employee();
    password = "password";
}    

/**
 * Create a user ID and print the user the details of their user account.
 */
public void createUser(Employee employee)
{  
    // Combine staff ID with authority key to make the user ID.
    userID = employee.getID() + "" + employee.getAuthorityLevel();

    // Check that there is a staff ID to create the user ID.
    // It also ensures that an employee profile has been created before an attempt
    // to make a user account.
    if(employee.getID() == null){
        System.out.println("There are no Employee details to make a User with.");
        System.out.println("Please enter the Employee details before you make a user");
    }
    else{
        System.out.println("Your user ID is: "+userID);
        System.out.println("Your user password is: "+password);
    }
}    

/**
 * @return The user ID.
 */
public String getUserID()
{
    return userID;
}

/**
 * @return The password.
 */
public String getPassword()
{
    return password;
}  
}

I want to access the userID and password getter methods in the User class to use in the Login class.

Login class

public class Login
{
private User user;  
private boolean accessGranted;
private String userID;
private String password;   
private boolean loggedIn;
private boolean loggedOut;
/**
 * Constructor for the Login class - initialise a user object.
 */
public Login()
{   
    user = new User();
}   

/**
 * Attempt to start a login session.
 */
public void login(String userID,String password)
{   
    // Check that credentials entered are correct for the account the user wishes to log in to.
    if((password == user.getPassword()) && (userID == user.getUserID())){
        accessGranted = true;
        if((accessGranted == true) && (userID.contains("H"))){
            System.out.println("Your login session has started.");
            System.out.println("You are now viewing Yuconz System as HR staff.");
        }
        if((accessGranted == true) && (userID.contains("D"))){
            System.out.println("Your login session has started.");
            System.out.println("You are now viewing Yuconz System as Director staff.");
        }
        if((accessGranted == true) && (userID.contains("E"))){
            System.out.println("Your login session has started.");
            System.out.println("You are now viewing Yuconz System as Employee staff.");
        }
        loggedIn = true;
    }
    else{
        System.out.println("ACCESS DENIED BRUTHA!");
    }
}    

One class creates the user account where the only details are a userID and a password. The other class is where the user can use the details of that account to login. In Login 's login method I am checking that the ID and password entered match the ID and password of the account that they are trying to access.

Answer 1

It seems that you never call public void createUser(Employee employee) on the instance of User.

SO

private String userID; in never initialized...

Try this :

public class User{

    private String userID;
    private String password;
    private Employee employee;
    private String authorityLevel;

    public User(Employee employee){  
        this.employee = employee;
        password = "password";
        createUser();
    }    

    private void createUser(){  
        userID = employee.getID() + "" + employee.getAuthorityLevel();

        if(userID == null){
            System.out.println("There are no Employee details to make a User with.");
            System.out.println("Please enter the Employee details before you make a user");
        }else{
            System.out.println("Your user ID is: "+userID);
            System.out.println("Your user password is: "+password);
        }
    }    

    public String getUserID(){
        return userID;
    }

    public String getPassword(){
        return password;
    }  
}

Passing the Employee the the User's constructor is the best solution if you need an instance of Employee to creat a User.

If you do not have any instance of Employee in your login but just an id and a password then you can change the User's constructor : :

public class User{
    private String userID;
    private String password;
    private String authorityLevel;

    public User(String userID, String password){  
        this.userID = userID;
        this.password = password;       
        checkUser();
    }    

    private void checkUser(){  
        if(userID == null){
            System.out.println("There are no Employee details to make a User with.");
            System.out.println("Please enter the Employee details before you make a user");
        }else{
            System.out.println("Your user ID is: " + userID);
            System.out.println("Your user password is: " + password);
        }
    }    
    //...
}

You can instanciate the User in the Login

public class Login

    private User user;

    public Login(){   
    }   

    public void login(String userID,String password){   
        user = new User(userID, password);
        //...

}

Answer 2

The strings userID and password belong to the Employee object. You're not initialising those values in your User class, this is why they are null .

You could do it like this

public String getUerID() {
    return employee.getUserID();

If you want them to belong to the User class the way you declared them in the class, you need to change your User constructor. eg

public User(String id, String pwd) {
    this.userID = id;
    this.password = pwd;
}

Then you need to figure out if you still want the Employee object or not.

You should reconsider some design decisions