class BirthDate
{
private int day;
private int month;
private int year;
private double time;

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

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

public void setDay(int d)
{
day=d;
}

public void setMonth(int m)
{
month=m;
}

public void setYear(int y)
{
year=y;
}

public int getDay()
{
return day;
}

public int getMonth()
{
return month;
}

public int getYear()
{
return year;
}

public void display()
{
System.out.println(day+ "-" + month+ "-" + year);
}
public void show()
{
System.out.println(day+ "-" + month+ "-" + year+"-" +time);
}
}

public class Test{
public static void main(String[] args)
{
Test test=new Test();
int date=9;
BirthDate d1=new BirthDate(7,7,1970);
BirthDate d2=new BirthDate(1,1,2000);
BirthDate d3=new BirthDate(1,1,2000,18);
test.change1(date);
test.change2(d1);
test.change3(d2);
System.out.println("date="+date);
d1.display();
d2.display();
d3.show();
}

public void change1(int i)
{
i=1234;
}

public void change2(BirthDate b)
{
b=new BirthDate(22,2,2004);
}

public void change3(BirthDate b)
{
b.setDay(22);
}
}

BirthDate.java:63: 类 Test 是公共的，应在名为 Test.java 的文件中声明public class Test{ ^1 错误
好吧~~去掉class Test 前的public
运行又来Exception in thread "main" java.lang.NoSuchMethodError: main
求指教

  class Test前面不能加public.
除了这个问题.   编译没问题，运行后的结果是:
date=9
7-7-1970
22-1-2000
1-1-2000-18.0
楼主编译如果还是报错的话  检查一下主函数有没有误删除。。运行的是不是Test

java.lang.NoSuchMethodError 这个报错的是说当应用程序试图调用类（静态或实例）的指定方法，而该类已不再具有该方法的定义。