编写MyDate类遇到问题

MyDate类的代码：

public class MyDate{
    private Calendar c=Calendar.getInstance();
    private String Pattern="yyyy-MM-dd";
    public MyDate() {
        super();
    }
    public MyDate(int y,int m,int d) {
        c.set(Calendar.YEAR, y);
        c.set(Calendar.MONTH, m);
        c.set(Calendar.DAY_OF_MONTH, d);

    }
    public MyDate(String source) {
        SimpleDateFormat sdf=new SimpleDateFormat(Pattern);
        try {
            c.setTime(sdf.parse(source));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    public MyDate(String source,String Pattern) {
        this.Pattern=Pattern;
        SimpleDateFormat sdf=new SimpleDateFormat(Pattern);
        try {
            c.setTime(sdf.parse(source));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }
    public MyDate after(int n){
        MyDate e=new MyDate(c.get(Calendar.YEAR),c.get(Calendar.MONTH)-1,c.get(Calendar.DAY_OF_MONTH) );
        e.c.add(Calendar.DAY_OF_MONTH, n);
        return e;

    }
    public MyDate before(int n){
        MyDate e=new MyDate(c.get(Calendar.YEAR),c.get(Calendar.MONTH)-1,c.get(Calendar.DAY_OF_MONTH));
        e.c.add(Calendar.DAY_OF_MONTH,-n);
        return e;
    }
    public Date getDate(){
        return c.getTime();

    }
    public Calendar getCalender(){
        return c;

    }
    public long getLong(){
        return c.getTimeInMillis();

    }
    public void setPattern(String pattern) {
        this.Pattern = pattern;
    }
    @Override
    public String toString() {
        SimpleDateFormat sdf=new SimpleDateFormat(Pattern);
        return sdf.format(c.getTime());
    }

}

上一个问题中这个代码没有给出来

首先，提问的时候可以选择“代码片”，该格式贴的才是代码，否则会被作为普通文本解析的。
其次，并没有看到异常信息呢。