diff --git a/jdk/test/com/alibaba/wisp/io/DatagramSocketTest.java b/jdk/test/com/alibaba/wisp/io/DatagramSocketTest.java
index 8d58480f92..59286021c8 100644
--- a/jdk/test/com/alibaba/wisp/io/DatagramSocketTest.java
+++ b/jdk/test/com/alibaba/wisp/io/DatagramSocketTest.java
@@ -64,7 +64,10 @@ public class DatagramSocketTest {
static public void testSendAndReceive() throws Exception {
CountDownLatch count = new CountDownLatch(1);
InetAddress host = InetAddress.getByName("localhost");
- int port = 9527;
+ int port = 0;
+ ServerSocket ss = new ServerSocket(port);
+ System.out.println("port get from os = " + port);
+ port = ss.getLocalPort();
DatagramSocket so = new DatagramSocket(port);
so.setSoTimeout(1_000);
final int loop = 1024;
patch.diff.log