程序如下：
import java.util.*;

class rr
{
LinkedList threadList = new LinkedList();
public int n=0;
public rr(int i,LinkedList thrList)
{
n=i;
threadList=thrList;
if(i!=0)
System.out.println(threadList.getFirst().n);
}

}

public class Fr {
public static void main(String s[]) {

LinkedList threadList=new LinkedList();
for(int i=0;i<2;i++)
{
rr obr=new rr(i,threadList);
threadList.add(obr);
}

}
}

　　是我发错程序了：下面我做过强制转换了啊，还是错
import java.util.*;

class rr
{
LinkedList threadList = new LinkedList();
public int n=0;
public rr(int i,LinkedList thrList)
{
n=i;
threadList=thrList;
if(i!=0)
System.out.println(（rr)threadList.getFirst().n);
}

}

public class Fr {
public static void main(String s[]) {

LinkedList threadList=new LinkedList();
for(int i=0;i<2;i++)
{
rr obr=new rr(i,threadList);
threadList.add(obr);
}

}
}