Try to stabilize SocketUtil

Author: marci4

src/test/java/org/java_websocket/issues/Issue879Test.java

@@ -57,7 +57,7 @@ public class Issue879Test {
   @Timeout(10000)
   @ParameterizedTest()
   @MethodSource("data")
-  public void QuickStopTest(int numberOfConnections) throws IOException, InterruptedException, URISyntaxException {
+  public void QuickStopTest(int numberOfConnections) throws InterruptedException, URISyntaxException {
     final boolean[] wasBindException = {false};
     final boolean[] wasConcurrentException = new boolean[1];
     final CountDownLatch countDownLatch = new CountDownLatch(1);

src/test/java/org/java_websocket/protocols/ProtocolHandshakeRejectionTest.java

@@ -58,7 +58,7 @@ public class ProtocolHandshakeRejectionTest {
   private int port;
 
   @BeforeEach
-  public void startServer() throws Exception {
+  public void startServer() {
     port = SocketUtil.getAvailablePort();
     thread = new Thread(
         new Runnable() {
@@ -488,6 +488,9 @@ public void testHandshakeRejectionTestCase29() throws Exception {
   }
 
   private void testProtocolRejection(int i, Draft_6455 draft) throws Exception {
+    do {
+      Thread.sleep(10);
+    }  while(serverSocket == null || !serverSocket.isBound());
     final int finalI = i;
     final CountDownLatch countDownLatch = new CountDownLatch(1);
     final WebSocketClient webSocketClient = new WebSocketClient(

src/test/java/org/java_websocket/util/SocketUtil.java

@@ -30,15 +30,13 @@
 
 public class SocketUtil {
 
-  public static int getAvailablePort() throws IOException {
-    ServerSocket srv = null;
-    try {
-      srv = new ServerSocket(0);
-      return srv.getLocalPort();
-    } finally {
-      if (srv != null) {
-        srv.close();
-      }
+    public static int getAvailablePort() {
+        while (true) {
+            try (ServerSocket srv = new ServerSocket(0)) {
+                return srv.getLocalPort();
+            } catch (IOException e) {
+                // Ignore
+            }
+        }
     }
-  }
 }