500 Internal Error

java.io.FileNotFoundException: /tmp/jetty-0.0.0.0-8107-radicifuturemagazine.war-_-www.radicifuturemagazine.it-3270188776237362569.dir/webapp (Is a directory)
	at java.io.RandomAccessFile.open0(Native Method)
	at java.io.RandomAccessFile.open(RandomAccessFile.java:316)
	at java.io.RandomAccessFile.(RandomAccessFile.java:243)
	at com.mandragola.webapp.HttpFileServer.serveFile(HttpFileServer.java:240)
	at com.mandragola.webapp.HttpFileServer.serveFile(HttpFileServer.java:56)
	at com.mandragola.zainet.App.lambda$init$43(App.java:129)
	at spark.RouteImpl$1.handle(RouteImpl.java:58)
	at spark.webserver.MatcherFilter.doFilter(MatcherFilter.java:162)
	at com.mandragola.zainet.MySparkFilter.doFilter(MySparkFilter.java:82)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1668)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:581)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:226)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1158)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:511)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1090)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:213)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:109)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:119)
	at org.eclipse.jetty.server.Server.handle(Server.java:517)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:308)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:242)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:273)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:95)
	at org.eclipse.jetty.io.SelectChannelEndPoint$2.run(SelectChannelEndPoint.java:75)
	at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.produceAndRun(ExecuteProduceConsume.java:213)
	at org.eclipse.jetty.util.thread.strategy.ExecuteProduceConsume.run(ExecuteProduceConsume.java:147)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:654)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:572)
	at java.lang.Thread.run(Thread.java:745)