The Vert.x API exposes the Netty API in its public API, allowing inte…

…ractions with the Netty API. Since Netty is evolving toward Netty 5, we should remove Netty API from the Vert.x public API in Vert.x 5 to have the opportunity to change the underlying Netty version used by Vert.x without worrying about the version of the Netty version.

Such API continues to exist in Vert.x 5 but is moved to internal API which more easily change, therefore experimented users of this API can continue to use it granted that the version of Vert.x 5 uses Netty 4.

In practice most users should not use this API, and the deprecation should be seen also as a signal toward users of this API.

src/main/java/io/vertx/core/Vertx.java

@@ -676,8 +676,10 @@ default <T> void executeBlocking(Handler<Promise<T>> blockingCodeHandler, Handle
    * Return the Netty EventLoopGroup used by Vert.x
    *
    * @return the EventLoopGroup
+   * @deprecated removed from public API in Vert.x 5
    */
   @GenIgnore(GenIgnore.PERMITTED_TYPE)
+  @Deprecated
   EventLoopGroup nettyEventLoopGroup();
 
   /**

src/main/java/io/vertx/core/buffer/Buffer.java

@@ -110,7 +110,9 @@ static Buffer buffer(byte[] bytes) {
    *
    * @param byteBuf the Netty ByteBuf
    * @return the buffer
+   * @deprecated removed from public API in Vert.x 5
    */
+  @Deprecated
   @GenIgnore(GenIgnore.PERMITTED_TYPE)
   static Buffer buffer(ByteBuf byteBuf) {
     Objects.requireNonNull(byteBuf);
@@ -705,7 +707,10 @@ default Object toJson() {
    * Returns the Buffer as a Netty {@code ByteBuf}.
    *
    * <p> The returned buffer is a duplicate that maintain its own indices.
+   *
+   * @deprecated removed from public API in Vert.x 5
    */
+  @Deprecated
   @GenIgnore(GenIgnore.PERMITTED_TYPE)
   ByteBuf getByteBuf();
 

src/main/java/io/vertx/core/impl/VertxInternal.java

@@ -15,6 +15,7 @@
 import io.netty.channel.EventLoop;
 import io.netty.channel.EventLoopGroup;
 import io.netty.resolver.AddressResolverGroup;
+import io.vertx.codegen.annotations.GenIgnore;
 import io.vertx.core.*;
 import io.vertx.core.http.HttpClient;
 import io.vertx.core.http.HttpClientOptions;

src/test/java/io/vertx/core/dns/HostnameResolutionTest.java

@@ -327,7 +327,7 @@ public void testAsyncResolveConnectIsNotifiedOnChannelEventLoop() throws Excepti
       CountDownLatch connectLatch = new CountDownLatch(1);
       Bootstrap bootstrap = new Bootstrap();
       bootstrap.channelFactory(((VertxInternal)vertx).transport().channelFactory(false));
-      bootstrap.group(vertx.nettyEventLoopGroup());
+      bootstrap.group(((VertxInternal) vertx).getEventLoopGroup());
       bootstrap.resolver(((VertxInternal) vertx).nettyAddressResolverGroup());
       bootstrap.handler(new ChannelInitializer<Channel>() {
         @Override