The following ConcurrentModificationException was encountered when using ICEpush with Cloud Push:

java.util.ConcurrentModificationException
    at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
    at java.util.HashMap$KeyIterator.next(HashMap.java:828)
    at org.icepush.LocalPushGroupManager.pruneParkedIDs(LocalPushGroupManager.java:252)
    at org.icepush.BlockingConnectionServer$RunningServer.service(BlockingConnectionServer.java:353)
    at org.icepush.BlockingConnectionServer.service(BlockingConnectionServer.java:96)
    at org.icepush.SequenceTaggingServer.service(SequenceTaggingServer.java:54)
    at org.icepush.ConfigurationServer.service(ConfigurationServer.java:93)
    at org.icepush.servlet.ThreadBlockingAdaptingServlet.service(ThreadBlockingAdaptingServlet.java:45)
    at org.icepush.servlet.EnvironmentAdaptingServlet.service(EnvironmentAdaptingServlet.java:52)
    at org.icepush.servlet.PathDispatcher.service(PathDispatcher.java:39)
    at org.icepush.servlet.BrowserDispatcher$BrowserEntry.service(BrowserDispatcher.java:117)
    at org.icepush.servlet.BrowserDispatcher.service(BrowserDispatcher.java:45)
    at org.icepush.servlet.PathDispatcher.service(PathDispatcher.java:39)
    at org.icepush.servlet.MainServlet.service(MainServlet.java:128)
    at org.icefaces.impl.push.servlet.ICEpushResourceHandler$ICEpushResourceHandlerImpl.handleResourceRequest(ICEpushResourceHandler.java:235)
    at org.icefaces.impl.push.servlet.ICEpushResourceHandler.handleResourceRequest(ICEpushResourceHandler.java:128)
    at org.icefaces.impl.push.DynamicResourceDispatcher.handleResourceRequest(DynamicResourceDispatcher.java:78)
    at org.icefaces.application.ResourceRegistry.handleResourceRequest(ResourceRegistry.java:138)
    at org.icefaces.impl.application.WindowScopeManager.handleSessionAwareResourceRequest(WindowScopeManager.java:68)
    at org.icefaces.impl.application.SessionAwareResourceHandlerWrapper.handleResourceRequest(SessionAwareResourceHandlerWrapper.java:40)
    at javax.faces.application.ResourceHandlerWrapper.handleResourceRequest(ResourceHandlerWrapper.java:125)
    at org.icefaces.impl.application.SessionTimeoutMonitor.handleSessionAwareResourceRequest(SessionTimeoutMonitor.java:71)
    at org.icefaces.impl.application.SessionAwareResourceHandlerWrapper.handleResourceRequest(SessionAwareResourceHandlerWrapper.java:40)
    at org.icefaces.mobi.component.qrcode.generator.QRCodeResourceHandler.handleResourceRequest(QRCodeResourceHandler.java:67)
    at javax.faces.application.ResourceHandlerWrapper.handleResourceRequest(ResourceHandlerWrapper.java:125)
    at org.icefaces.impl.application.AuxUploadResourceHandler.handleResourceRequest(AuxUploadResourceHandler.java:82)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:591)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1009)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
    at java.lang.Thread.run(Thread.java:680)