这两个程序为什么会有区别..?

[ShingU]

//程序1
import java.io.*;

class Test
{
public static void main(String [] args) throws IOException
{
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

System.err.println("Type in some lines.");

while (true)
{
if (in.readLine().length() == 0)
break;

System.out.println("The line \"" + in.readLine() + "\"");
}

System.out.println("The end.");
}
}

//程序2
import java.io.*;

class Test
{
public static void main(String [] args) throws IOException
{
BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

System.err.println("Type some lines.");

while (true)
{
String str = din.readLine().trim();

if (str.length() == 0)
break;

System.out.println("The line \"" + str + "\"");
}

System.out.println("The end.");
}
}

[新来的萌新]

大兄弟!提问可不可以跟点分!

[升烟张诚]

第一个程序不是有两个readline吗，就是输入两句，只输出后一句