compiler.lib.ir_framework.shared.TestFrameworkSocket should listen on loopback address only

compiler.lib.ir_framework.shared.TestFrameworkSocket is a test specific class in test/hotspot/jtreg/compiler/lib/ir_framework/. This class creates a ServerSocket which currently binds to "any address". To prevent interference from other hosts on the network, this test class should bind to only loopback address. The client side of this test class should then create a Socket against the loopback address.

An (untested) patch for this change would look something like:

diff --git a/test/hotspot/jtreg/compiler/lib/ir_framework/shared/TestFrameworkSocket.java b/test/hotspot/jtreg/compiler/lib/ir_framework/shared/TestFrameworkSocket.java
index 988df309718..c59f432f5ff 100644
--- a/test/hotspot/jtreg/compiler/lib/ir_framework/shared/TestFrameworkSocket.java
+++ b/test/hotspot/jtreg/compiler/lib/ir_framework/shared/TestFrameworkSocket.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -29,6 +29,8 @@
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.PrintWriter;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.concurrent.ExecutionException;
@@ -47,7 +49,6 @@ public class TestFrameworkSocket implements AutoCloseable {
     private static final int SERVER_PORT = Integer.getInteger(SERVER_PORT_PROPERTY, -1);
 
     private static final boolean REPRODUCE = Boolean.getBoolean("Reproduce");
- private static final String HOSTNAME = null;
     private static Socket clientSocket = null;
     private static PrintWriter clientWriter = null;
 
@@ -58,7 +59,8 @@ public class TestFrameworkSocket implements AutoCloseable {
 
     public TestFrameworkSocket() {
         try {
- serverSocket = new ServerSocket(0);
+ serverSocket = new ServerSocket();
+ serverSocket.bind(new InetSocketAddress(InetAddress.getLoopbackAddress(), 0));
         } catch (IOException e) {
             throw new TestFrameworkException("Failed to create TestFramework server socket", e);
         }
@@ -132,7 +134,7 @@ public static void write(String msg, String tag, boolean stdout) {
         try {
             // Keep the client socket open until the test VM terminates (calls closeClientSocket before exiting main()).
             if (clientSocket == null) {
- clientSocket = new Socket(HOSTNAME, SERVER_PORT);
+ clientSocket = new Socket(InetAddress.getLoopbackAddress(), SERVER_PORT);
                 clientWriter = new PrintWriter(clientSocket.getOutputStream(), true);
             }
             if (stdout) {




(I haven't done a thorough check to see if there are other test classes which use this TestFrameworkSocket class and thus would need to change their Socket instance creation to use the loopback address)