Java，无法验证字符串

Question

我一直在构造一个带有一些参数（名称，id等）的新员工。我用一个简单的if / else在部门验证和名称编码中编写代码。由于某些原因，即使满足条件，它也总是会引发错误。我是Java的新手，我希望获得一些帮助。谢谢！

public class Employee {
    int empId;
    String empName;
    String empDesig;
    String empDept;

    public void setEmpName(String name) {
        if (name == null) {
            System.out.println("Name cannot be null. Close app and try 
            again.");
            System.exit(1);;
        }
    }
    public void setEmptDesig(String desig) {
        if(desig == "Developer" || desig == "Tester" || desig == "Lead" || 
        desig == "Manager") {
            return;
        } else {
            System.out.println("Designation is invalid. Close app and try 
            again.");
            System.exit(1);
        }
    }
    public void setEmptDept(String dept) {
        if(dept == "TTH" || dept == "RCM" || dept == "Digital" || dept == 
            "DevOps") {
            return;
        } else {
            System.out.println("Department is invalid. Close app and try again.");
            System.exit(1);
        }
    }

    public Employee(int id,String name,String desig, String dept ) {
        setEmpName(name);
        setEmptDesig(desig);
        setEmptDept(dept);
        empId= id;
        empName = name;
        empDesig = desig;
        empDept = dept;
    }


}
public class CreateEmployee {

    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter ID");
        String id = scan.nextLine();
        int idInt = Integer.parseInt(id);
        System.out.println("Enter Name");
        String name = scan.nextLine();
        System.out.println("Enter Designation");
        String desig = scan.nextLine();
        System.out.println("Enter Department");
        String dept = scan.nextLine();
        Employee emp = new Employee(idInt,name,desig,dept);
        System.out.println(emp.empId +" "+ emp.empName + " " + emp.empDesig + 
        " " + emp.empDept);

    }

}

即使假定符合条件，也会始终触发错误。