Move the startup of the WebSocketWorker inside of run()

src/main/java/org/java_websocket/server/WebSocketServer.java

@@ -228,10 +228,6 @@ public void start() {
 		if( selectorthread != null )
 			throw new IllegalStateException( getClass().getName() + " can only be started once." );
 		new Thread( this ).start();
-
-		for( WebSocketWorker ex : decoders ){
-			ex.start();
-		}
 	}
 
 	/**
@@ -510,6 +506,9 @@ private boolean doSetupSelectorAndServerThread() {
 			selector = Selector.open();
 			server.register( selector, server.validOps() );
 			startConnectionLostTimer();
+			for( WebSocketWorker ex : decoders ){
+				ex.start();
+			}
 			onStart();
 		} catch ( IOException ex ) {
 			handleFatal( null, ex );

src/test/java/org/java_websocket/issues/Issue855Test.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (c) 2010-2019 Nathan Rajlich
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following
+ * conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+package org.java_websocket.issues;
+
+import org.java_websocket.WebSocket;
+import org.java_websocket.client.WebSocketClient;
+import org.java_websocket.handshake.ClientHandshake;
+import org.java_websocket.handshake.ServerHandshake;
+import org.java_websocket.server.WebSocketServer;
+import org.java_websocket.util.SocketUtil;
+import org.junit.Test;
+
+import java.net.InetSocketAddress;
+import java.net.URI;
+import java.util.concurrent.CountDownLatch;
+
+public class Issue855Test {
+
+    CountDownLatch countServerDownLatch = new CountDownLatch(1);
+    CountDownLatch countDownLatch = new CountDownLatch(1);
+
+    @Test(timeout = 2000)
+    public void testIssue() throws Exception {
+        int port = SocketUtil.getAvailablePort();
+        WebSocketClient webSocket = new WebSocketClient(new URI("ws://localhost:" + port)) {
+            @Override
+            public void onOpen(ServerHandshake handshakedata) {
+                countDownLatch.countDown();
+            }
+
+            @Override
+            public void onMessage(String message) {
+
+            }
+
+            @Override
+            public void onClose(int code, String reason, boolean remote) {
+            }
+
+            @Override
+            public void onError(Exception ex) {
+
+            }
+        };
+        WebSocketServer server = new WebSocketServer(new InetSocketAddress(port)) {
+            @Override
+            public void onOpen(WebSocket conn, ClientHandshake handshake) {
+                conn.close();
+            }
+
+            @Override
+            public void onClose(WebSocket conn, int code, String reason, boolean remote) {
+            }
+
+            @Override
+            public void onMessage(WebSocket conn, String message) {
+
+            }
+
+            @Override
+            public void onError(WebSocket conn, Exception ex) {
+
+            }
+
+            @Override
+            public void onStart() {
+                countServerDownLatch.countDown();
+            }
+        };
+        new Thread(server).start();
+        countServerDownLatch.await();
+        webSocket.connectBlocking();
+        server.stop();
+    }
+}