ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.v

Hi guys, I received this error when trying to log into my Vaadin UI, any idea what is going on here?

Vaadin 8.1.6,
INFO: Atmosphere is using async support: org.atmosphere.container.JSR356AsyncSupport running under container: jetty/9.4.8.v20171121 using javax.servlet/3.0 and jsr356/WebSocket API

javax.servlet.ServletException: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:146)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:383)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.handleExceptionDuringRequest (VaadinService.java:1620)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1580)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.readFromHttpSession (VaadinService.java:2152)
    at com.vaadin.server.VaadinService.loadSession (VaadinService.java:2131)
    at com.vaadin.server.VaadinService.getExistingSession (VaadinService.java:904)
    at com.vaadin.server.VaadinService.doFindOrCreateVaadinSession (VaadinService.java:749)
    at com.vaadin.server.VaadinService.findOrCreateVaadinSession (VaadinService.java:723)
    at com.vaadin.server.VaadinService.findVaadinSession (VaadinService.java:581)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1562)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
[WARNING]
 /
javax.servlet.ServletException: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:146)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:383)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.handleExceptionDuringRequest (VaadinService.java:1620)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1580)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.readFromHttpSession (VaadinService.java:2152)
    at com.vaadin.server.VaadinService.loadSession (VaadinService.java:2131)
    at com.vaadin.server.VaadinService.getExistingSession (VaadinService.java:904)
    at com.vaadin.server.VaadinService.doFindOrCreateVaadinSession (VaadinService.java:749)
    at com.vaadin.server.VaadinService.findOrCreateVaadinSession (VaadinService.java:723)
    at com.vaadin.server.VaadinService.findVaadinSession (VaadinService.java:581)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1562)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
[WARNING]
 /PUSH
javax.servlet.ServletException: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:146)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:383)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.handleExceptionDuringRequest (VaadinService.java:1620)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1580)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.readFromHttpSession (VaadinService.java:2152)
    at com.vaadin.server.VaadinService.loadSession (VaadinService.java:2131)
    at com.vaadin.server.VaadinService.getExistingSession (VaadinService.java:904)
    at com.vaadin.server.VaadinService.doFindOrCreateVaadinSession (VaadinService.java:749)
    at com.vaadin.server.VaadinService.findOrCreateVaadinSession (VaadinService.java:723)
    at com.vaadin.server.VaadinService.findVaadinSession (VaadinService.java:581)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1562)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
[WARNING]
 /favicon.ico
javax.servlet.ServletException: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:146)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: javax.servlet.ServletException: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:383)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: com.vaadin.server.ServiceException: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.handleExceptionDuringRequest (VaadinService.java:1620)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1580)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)
Caused by: java.lang.ClassCastException: com.vaadin.server.VaadinSession cannot be cast to com.vaadin.server.VaadinSession
    at com.vaadin.server.VaadinService.readFromHttpSession (VaadinService.java:2152)
    at com.vaadin.server.VaadinService.loadSession (VaadinService.java:2131)
    at com.vaadin.server.VaadinService.getExistingSession (VaadinService.java:904)
    at com.vaadin.server.VaadinService.doFindOrCreateVaadinSession (VaadinService.java:749)
    at com.vaadin.server.VaadinService.findOrCreateVaadinSession (VaadinService.java:723)
    at com.vaadin.server.VaadinService.findVaadinSession (VaadinService.java:581)
    at com.vaadin.server.VaadinService.handleRequest (VaadinService.java:1562)
    at com.vaadin.server.VaadinServlet.service (VaadinServlet.java:381)
    at javax.servlet.http.HttpServlet.service (HttpServlet.java:790)
    at org.eclipse.jetty.servlet.ServletHolder.handle (ServletHolder.java:860)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle (ServletHandler.java:535)
    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.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:190)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle (SessionHandler.java:1595)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle (ScopedHandler.java:188)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle (ContextHandler.java:1253)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:168)
    at org.eclipse.jetty.servlet.ServletHandler.doScope (ServletHandler.java:473)
    at org.eclipse.jetty.server.session.SessionHandler.doScope (SessionHandler.java:1564)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope (ScopedHandler.java:166)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope (ContextHandler.java:1155)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle (ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle (ContextHandlerCollection.java:219)
    at org.eclipse.jetty.server.handler.HandlerCollection.handle (HandlerCollection.java:126)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle (HandlerWrapper.java:132)
    at org.eclipse.jetty.server.Server.handle (Server.java:530)
    at org.eclipse.jetty.server.HttpChannel.handle (HttpChannel.java:347)
    at org.eclipse.jetty.server.HttpConnection.onFillable (HttpConnection.java:256)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded (AbstractConnection.java:279)
    at org.eclipse.jetty.io.FillInterest.fillable (FillInterest.java:102)
    at org.eclipse.jetty.io.ChannelEndPoint$2.run (ChannelEndPoint.java:124)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce (EatWhatYouKill.java:247)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.produce (EatWhatYouKill.java:140)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run (EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run (ReservedThreadExecutor.java:382)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob (QueuedThreadPool.java:708)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run (QueuedThreadPool.java:626)
    at java.lang.Thread.run (Thread.java:748)

Maybe it’s the Atmosphere doesn’t play well with your jetty server, have you tried some other jetty server? like 9.3.9.v20160517?

This usually means that there are two com.vaadin.server.VaadinSession classes loaded by two different classloaders. This could be some leftover jar file in Jetty’s temp directory getting loaded along with your WAR file. Try cleaning all possible Jetty temp dirs you can find.