ERROR --- [ctor-http-nio-3] r.i.netty.channel.CloseableContextHandler  : Handler failure while no child channelOperation was present
io.netty.handler.ssl.NotSslRecordException: not an SSL/TLS record: ...
at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1178) [netty-handler-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1243) [netty-handler-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:502) [netty-codec-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:441) [netty-codec-4.1.31.Final.jar:4.1.31.Final]
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:278) [netty-codec-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1434) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:965) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:648) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:583) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:500) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:462) [netty-transport-4.1.31.Final.jar:4.1.31.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:897) [netty-common-4.1.31.Final.jar:4.1.31.Final]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_171]

@ExceptionHandler(NotSslRecordException.class)
public ResponseEntity<Void> exceptionHandler(NotSslRecordException ex) {
    ...
}