<div dir="ltr">I just updated to Java 9 and have started getting the following exception:<div><br></div><font face="monospace">exampleJVM[ERROR] Oct 09, 2017 11:45:35 AM io.undertow.server.DirectByteBufferDeallocator &lt;clinit&gt;<br>exampleJVM[ERROR] ERROR: UT005091: Failed to initialize DirectByteBufferDeallocator<br>exampleJVM[ERROR] java.lang.ClassNotFoundException: sun.misc.Cleaner<br>exampleJVM[ERROR]       at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582)<br>exampleJVM[ERROR]       at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:185)<br>exampleJVM[ERROR]       at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:496)<br>exampleJVM[ERROR]       at java.base/java.lang.Class.forName0(Native Method)<br>exampleJVM[ERROR]       at java.base/java.lang.Class.forName(Class.java:292)<br>exampleJVM[ERROR]       at io.undertow.server.DirectByteBufferDeallocator.&lt;clinit&gt;(DirectByteBufferDeallocator.java:23)<br>exampleJVM[ERROR]       at io.undertow.server.DefaultByteBufferPool.queueIfUnderMax(DefaultByteBufferPool.java:207)<br>exampleJVM[ERROR]       at io.undertow.server.DefaultByteBufferPool.freeInternal(DefaultByteBufferPool.java:199)<br>exampleJVM[ERROR]       at io.undertow.server.DefaultByteBufferPool.access$200(DefaultByteBufferPool.java:41)<br>exampleJVM[ERROR]       at io.undertow.server.DefaultByteBufferPool$DefaultPooledBuffer.close(DefaultByteBufferPool.java:269)<br>exampleJVM[ERROR]       at io.undertow.conduits.DeflatingStreamSinkConduit.deflateData(DeflatingStreamSinkConduit.java:495)<br>exampleJVM[ERROR]       at io.undertow.conduits.DeflatingStreamSinkConduit.write(DeflatingStreamSinkConduit.java:117)<br>exampleJVM[ERROR]       at io.undertow.conduits.DeflatingStreamSinkConduit.write(DeflatingStreamSinkConduit.java:138)<br>exampleJVM[ERROR]       at org.xnio.conduits.ConduitStreamSinkChannel.write(ConduitStreamSinkChannel.java:154)<br>exampleJVM[ERROR]       at io.undertow.channels.DetachableStreamSinkChannel.write(DetachableStreamSinkChannel.java:187)<br>exampleJVM[ERROR]       at io.undertow.server.HttpServerExchange$WriteDispatchChannel.write(HttpServerExchange.java:2046)<br>exampleJVM[ERROR]       at io.undertow.io.AsyncSenderImpl.send(AsyncSenderImpl.java:219)<br>exampleJVM[ERROR]       at io.undertow.io.AsyncSenderImpl.send(AsyncSenderImpl.java:310)<br>exampleJVM[ERROR]       at io.undertow.io.AsyncSenderImpl.send(AsyncSenderImpl.java:282)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation$.handleStandard(UndertowServerImplementation.scala:250)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation$.response(UndertowServerImplementation.scala:169)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation.$anonfun$requestHandler$1(UndertowServerImplementation.scala:100)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation.$anonfun$requestHandler$1$adapted(UndertowServerImplementation.scala:97)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation$.handle$1(UndertowServerImplementation.scala:126)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation$.processRequest(UndertowServerImplementation.scala:162)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation.requestHandler(UndertowServerImplementation.scala:97)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation.$anonfun$handleRequest$1(UndertowServerImplementation.scala:90)<br>exampleJVM[ERROR]       at io.youi.ErrorSupport.errorSupport(ErrorSupport.scala:11)<br>exampleJVM[ERROR]       at io.youi.ErrorSupport.errorSupport$(ErrorSupport.scala:10)<br>exampleJVM[ERROR]       at io.youi.example.ServerExampleApplication$.errorSupport(ServerExampleApplication.scala:8)<br>exampleJVM[ERROR]       at io.youi.server.UndertowServerImplementation.handleRequest(UndertowServerImplementation.scala:74)<br>exampleJVM[ERROR]       at io.undertow.server.handlers.encoding.EncodingHandler.handleRequest(EncodingHandler.java:72)<br>exampleJVM[ERROR]       at io.undertow.server.Connectors.executeRootHandler(Connectors.java:332)<br>exampleJVM[ERROR]       at io.undertow.server.protocol.http.HttpReadListener.handleEventWithNoRunningRequest(HttpReadListener.java:254)<br>exampleJVM[ERROR]       at io.undertow.server.protocol.http.HttpReadListener.handleEvent(HttpReadListener.java:136)<br>exampleJVM[ERROR]       at io.undertow.server.protocol.http.HttpOpenListener.handleEvent(HttpOpenListener.java:151)<br>exampleJVM[ERROR]       at io.undertow.server.protocol.http.HttpOpenListener.handleEvent(HttpOpenListener.java:92)<br>exampleJVM[ERROR]       at io.undertow.server.protocol.http.HttpOpenListener.handleEvent(HttpOpenListener.java:51)<br>exampleJVM[ERROR]       at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)<br>exampleJVM[ERROR]       at org.xnio.ChannelListeners$10.handleEvent(ChannelListeners.java:291)<br>exampleJVM[ERROR]       at org.xnio.ChannelListeners$10.handleEvent(ChannelListeners.java:286)<br>exampleJVM[ERROR]       at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)<br>exampleJVM[ERROR]       at org.xnio.nio.QueuedNioTcpServer$1.run(QueuedNioTcpServer.java:129)<br>exampleJVM[ERROR]       at org.xnio.nio.WorkerThread.safeRun(WorkerThread.java:582)</font><br>exampleJVM[ERROR]       at org.xnio.nio.WorkerThread.run(WorkerThread.java:466)</div>