关于udp发送的问题

代码中在发送端指定了10000端口，但在接收端指定了10000接受后，DatagramPacket.getPort()却不是10000怎么回事儿？
代码：
send:String strinfo="mytest";
try {
ds = new DatagramSocket();
ds.send(new DatagramPacket(strinfo.getBytes(),
strinfo.length(),
InetAddress.getByName("10.161.33.224"),10000));
ds.close();
System.out.println("send ok");receive:
DatagramSocket ds=new DatagramSocket(10000);

byte[] buf=new byte[1024];
DatagramPacket dp=new  DatagramPacket(buf,1024);

ds.receive(dp);
System.out.println(new String(dp.getData(),0,dp.getLength()));
System.out.println("from: "+ dp.getAddress().getHostAddress()
+":"+dp.getPort());
ds.close();