包含软件包名称时出现错误“找不到符号”

Question

在以下代码中，只要我的代码没有在文件顶部声明一个程序包，我的IDE（VS代码）就会给我一个错误：The declared package does not match the expected package “”，但代码可以正常运行。但是，当我尝试声明该程序包时，IDE会显示错误已得到修复，但是在完成cannot find symbol时我可能会出错。

为什么在包含cannot find symbol时出现package [name of parent directly]错误？

//package studentprofilechallenge;    
class Main {
    public static void main(String[] args) {
        StudentProfile p1 = new StudentProfile("John", "Doe", 2019, 3.5, "IT");
        StudentProfile p2 = new StudentProfile("Jane", "Doe", 2016, 3.3, "Public Health");
        
        System.out.println(
                "Student named " + p2.firstName + " " + p2.lastName + "\'s graduation date is " 

    + p2.endYear + ".");
        }
    }

-

//package studentprofilechallenge; 
    class StudentProfile {
    String firstName;
    String lastName;
    int endYear;
    double GPA;
    String major;
    public static String universityName = "X University";

    public StudentProfile(
            String firstName,
            String lastName,
            int endYear,
            double GPA, 
            String major) {
            
        this.firstName = firstName;
        this.lastName = lastName;
        this.endYear = endYear;
        this.GPA = GPA;
        this.major = major;
    }

    public void incrementEndYear() {
        this.endYear = this.endYear + 1;
    }
    public void decrementEndYear(){
        this.endYear = this.endYear-1;
    }
}