Enforce an RFC valid Accept value for remote dev requests

The default Accept header defined in
sun.net.www.protocol.http.HttpURLConnection is invalid and
does not respect the RFC so we override it with a valid value.
RESTEasy is quite strict regarding the RFC and throws an error.
Note that this is just the default HttpURLConnection header value
made valid.
See https://bugs.openjdk.java.net/browse/JDK-8163921
and https://bugs.openjdk.java.net/browse/JDK-8177439

Fixes quarkusio#20904

extensions/vertx-http/deployment/src/main/java/io/quarkus/vertx/http/deployment/devmode/HttpRemoteDevClient.java

@@ -32,6 +32,16 @@ public class HttpRemoteDevClient implements RemoteDevClient {
 
     private final Logger log = Logger.getLogger(HttpRemoteDevClient.class);
 
+    /**
+     * The default Accept header defined in sun.net.www.protocol.http.HttpURLConnection is invalid and
+     * does not respect the RFC so we override it with a valid value.
+     * RESTEasy is quite strict regarding the RFC and throws an error.
+     * Note that this is just the default HttpURLConnection header value made valid.
+     * See https://bugs.openjdk.java.net/browse/JDK-8163921 and https://bugs.openjdk.java.net/browse/JDK-8177439
+     * and https://github.com/quarkusio/quarkus/issues/20904
+     */
+    private static final String DEFAULT_ACCEPT = "text/html, image/gif, image/jpeg; q=0.2, */*; q=0.2";
+
     private final String url;
     private final String password;
     private final long reconnectTimeoutMillis;
@@ -95,6 +105,7 @@ private void sendData(Map.Entry<String, byte[]> entry, String session) throws IO
             connection = (HttpURLConnection) new URL(url + "/" + entry.getKey()).openConnection();
             connection.setRequestMethod("PUT");
             connection.setDoOutput(true);
+            connection.setRequestProperty(HttpHeaders.ACCEPT.toString(), DEFAULT_ACCEPT);
             connection.addRequestProperty(HttpHeaders.CONTENT_TYPE.toString(), RemoteSyncHandler.APPLICATION_QUARKUS);
             connection.addRequestProperty(RemoteSyncHandler.QUARKUS_SESSION_COUNT, Integer.toString(currentSessionCounter));
 
@@ -120,6 +131,7 @@ private String doConnect(RemoteDevState initialState, Function<Set<String>, Map<
 
             HttpURLConnection connection = (HttpURLConnection) new URL(url + RemoteSyncHandler.CONNECT)
                     .openConnection();
+            connection.setRequestProperty(HttpHeaders.ACCEPT.toString(), DEFAULT_ACCEPT);
             connection.addRequestProperty(HttpHeaders.CONTENT_TYPE.toString(), RemoteSyncHandler.APPLICATION_QUARKUS);
             //for the connection we use the hash of the password and the contents
             //this can be replayed, but only with the same contents, and this does not affect the server
@@ -195,6 +207,7 @@ public void run() {
                     //long polling request
                     //we always send the current problem state
                     connection = (HttpURLConnection) devUrl.openConnection();
+                    connection.setRequestProperty(HttpHeaders.ACCEPT.toString(), DEFAULT_ACCEPT);
                     connection.setRequestMethod("POST");
                     connection.addRequestProperty(HttpHeaders.CONTENT_TYPE.toString(), RemoteSyncHandler.APPLICATION_QUARKUS);
                     connection.addRequestProperty(RemoteSyncHandler.QUARKUS_SESSION_COUNT,
@@ -223,6 +236,7 @@ public void run() {
                             }
                             log.info("deleting " + file);
                             connection = (HttpURLConnection) new URL(url + "/" + file).openConnection();
+                            connection.setRequestProperty(HttpHeaders.ACCEPT.toString(), DEFAULT_ACCEPT);
                             connection.setRequestMethod("DELETE");
                             connection.addRequestProperty(HttpHeaders.CONTENT_TYPE.toString(),
                                     RemoteSyncHandler.APPLICATION_QUARKUS);
@@ -270,6 +284,7 @@ private String waitForRestart(RemoteDevState initialState,
             while (System.currentTimeMillis() < timeout) {
                 try {
                     HttpURLConnection connection = (HttpURLConnection) probeUrl.openConnection();
+                    connection.setRequestProperty(HttpHeaders.ACCEPT.toString(), DEFAULT_ACCEPT);
                     connection.setRequestMethod("POST");
                     connection.addRequestProperty(HttpHeaders.CONTENT_TYPE.toString(), RemoteSyncHandler.APPLICATION_QUARKUS);
                     IoUtil.readBytes(connection.getInputStream());