How can i code simple login method to multi users?

// login method .. open the page depend in user if admin or not

public String Login() {

    for(Employees emp1 : Employees.theAllEmp) {
        if(emp1.getEmail().equals(emp.getEmail()))
        {
            if(emp1.getPassword().equals(emp.getPassword()))
            {
                if (emp1.getAdmin() == 0) {

                    return "adminView.xhtml?faces-redirect=true";
                } else if (emp1.getAdmin() == 1) {
                    return "employeesView.xhtml?faces-redirect=true";
                } else {
                    FacesContext.getCurrentInstance().addMessage(null,
                            new FacesMessage(FacesMessage.SEVERITY_ERROR, "No such Email", "No such Email"));
                    return null;
                }
            }
        }

    }
    return null;
}