Keycloak startup fails (undertow request failed HttpServerExchange) - wildfly

Question

I'm currently trying to get a standalone installation of Keycloak up and running.
My setup is a Windows Server 2019 and I tried multiple versions of Keycloak including 12.04 and 18.0 (wildfly). I tried both JRE 8 and JRE 11 with the same result.
After unpacking the keycloak.zip file I haven't done any configuration changes. When starting the standalone.bat I get the following error message and the server doesn't respond on http://localhost:8080
07:48:23,952 INFO [org.wildfly.extension.undertow] (ServerService Thread Pool -- 68) WFLYUT0021: Registered web context: '/auth' for server 'default-server'
07:48:24,067 INFO [org.jboss.as.server] (ServerService Thread Pool -- 55) WFLYSRV0010: Deployed "keycloak-server.war" (runtime-name : "keycloak-server.war")
07:48:24,138 INFO [org.jboss.as.server] (Controller Boot Thread) WFLYSRV0212: Resuming server
07:48:24,143 INFO [org.jboss.as] (Controller Boot Thread) WFLYSRV0025: Keycloak 12.0.4 (WildFly Core 13.0.3.Final) started in 35987ms - Started 589 of 867 services (585 services are lazy, passive or on-demand)
07:48:24,148 INFO [org.jboss.as] (Controller Boot Thread) WFLYSRV0060: Http management interface listening on http://127.0.0.1:9990/management
07:48:24,150 INFO [org.jboss.as] (Controller Boot Thread) WFLYSRV0051: Admin console listening on http://127.0.0.1:9990
07:48:30,333 ERROR [io.undertow.request] (default task-1) UT005071: Undertow request failed HttpServerExchange{ GET /auth/}: java.io.IOError: java.io.FileNotFoundException: Invalid file path
at org.xnio.conduits.Conduits$1.run(Conduits.java:237)
at org.xnio.conduits.Conduits$1.run(Conduits.java:227)
at java.security.AccessController.doPrivileged(Native Method)
at org.xnio.conduits.Conduits.<clinit>(Conduits.java:227)
at io.undertow.conduits.AbstractFixedLengthStreamSinkConduit.writeFinal(AbstractFixedLengthStreamSinkConduit.java:175)
at org.xnio.conduits.ConduitStreamSinkChannel.writeFinal(ConduitStreamSinkChannel.java:104)
at io.undertow.channels.DetachableStreamSinkChannel.writeFinal(DetachableStreamSinkChannel.java:195)
at io.undertow.server.HttpServerExchange$WriteDispatchChannel.writeFinal(HttpServerExchange.java:2160)
at io.undertow.servlet.spec.ServletOutputStreamImpl.writeBufferBlocking(ServletOutputStreamImpl.java:573)
at io.undertow.servlet.spec.ServletOutputStreamImpl.close(ServletOutputStreamImpl.java:610)
at io.undertow.servlet.spec.HttpServletResponseImpl.closeStreamAndWriter(HttpServletResponseImpl.java:497)
at io.undertow.servlet.spec.HttpServletResponseImpl.responseDone(HttpServletResponseImpl.java:586)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:328)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:78)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:133)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:130)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:249)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:78)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:99)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:387)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:841)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1348)
at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1280)
at java.lang.Thread.run(Thread.java:750)
Caused by: java.io.FileNotFoundException: Invalid file path
at java.io.FileOutputStream.<init>(FileOutputStream.java:206)
at java.io.FileOutputStream.<init>(FileOutputStream.java:101)
at org.xnio.conduits.Conduits$1.run(Conduits.java:232)
... 33 more
07:48:31,387 ERROR [io.undertow.request] (default task-1) UT005071: Undertow request failed HttpServerExchange{ GET /auth/}: java.lang.NoClassDefFoundError: Could not initialize class org.xnio.conduits.Conduits
at io.undertow.conduits.AbstractFixedLengthStreamSinkConduit.writeFinal(AbstractFixedLengthStreamSinkConduit.java:175)
at org.xnio.conduits.ConduitStreamSinkChannel.writeFinal(ConduitStreamSinkChannel.java:104)
at io.undertow.channels.DetachableStreamSinkChannel.writeFinal(DetachableStreamSinkChannel.java:195)
at io.undertow.server.HttpServerExchange$WriteDispatchChannel.writeFinal(HttpServerExchange.java:2160)
at io.undertow.servlet.spec.ServletOutputStreamImpl.writeBufferBlocking(ServletOutputStreamImpl.java:573)
at io.undertow.servlet.spec.ServletOutputStreamImpl.close(ServletOutputStreamImpl.java:610)
at io.undertow.servlet.spec.HttpServletResponseImpl.closeStreamAndWriter(HttpServletResponseImpl.java:497)
at io.undertow.servlet.spec.HttpServletResponseImpl.responseDone(HttpServletResponseImpl.java:586)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:328)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:78)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:133)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:130)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at org.wildfly.extension.undertow.security.SecurityContextThreadSetupAction.lambda$create$0(SecurityContextThreadSetupAction.java:105)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at org.wildfly.extension.undertow.deployment.UndertowDeploymentInfoService$UndertowThreadSetupAction.lambda$create$0(UndertowDeploymentInfoService.java:1530)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:249)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:78)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:99)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:387)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:841)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:1990)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1486)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1377)
at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1280)
at java.lang.Thread.run(Thread.java:750)
Any ideas why this error occurs?
Kind regards
Dennis

Answer 1

we were facing the same issue, our problem was JAVA was not installed correctly, check if you have correctly installed java.
try with oracle jdk 15, it worked for us.