JDWP-Handshake when remote debugging？

[haobo zhang]

when i debug alluxio use remote debugg，the below exceptions occurs？

could some brother  help me？

```java

Listening for transport dt_socket at address: 6606

Debugger failed to attach: handshake failed - received >HEAD / HTTP/1.< - expected >JDWP-Handshake<

Oct 26, 2021 2:22:03 PM io.grpc.netty.NettyServerTransport notifyTerminated

INFO: Transport failed

io.netty.handler.codec.http2.Http2Exception: Unexpected HTTP/1.x request: HEAD /

        at io.netty.handler.codec.http2.Http2Exception.connectionError(Http2Exception.java:103)

        at io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.readClientPrefaceString(Http2ConnectionHandler.java:302)

        at io.netty.handler.codec.http2.Http2ConnectionHandler$PrefaceDecoder.decode(Http2ConnectionHandler.java:239)

        at io.netty.handler.codec.http2.Http2ConnectionHandler.decode(Http2ConnectionHandler.java:438)

        at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:501)

        at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:440)

        at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:276)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357)

        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379)

        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365)

        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919)

        at io.netty.channel.epoll.AbstractEpollStreamChannel$EpollStreamUnsafe.epollInReady(AbstractEpollStreamChannel.java:795)

        at io.netty.channel.epoll.EpollEventLoop.processReady(EpollEventLoop.java:475)

        at io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:378)

        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)

        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)

        at java.lang.Thread.run(Thread.java:748)

```

[sanjay...@google.com]

Looks like port 6606 is used for both JDPA (remote debugging) and the gRPC server. If that's true you want to use a different port for remote debugging. See https://docs.oracle.com/javase/7/docs/technotes/guides/jpda/conninv.html . Your remote debugger should then also connect to that different port.