java 构造方法执行过程内存分析

package Demo;

public class BirthDate {
    private int day;
    private int month;
    private int year;
    
    public BirthDate(int d, int m, int y) {
        day = d;
        month = m;
        year = y;
    }
}

package Demo;

public class Demo {
    public static void main(String[] args) {
        BirthDate d1 = new BirthDate(7, 7, 1970);
    }
}