使用jfinal-undertow作为服务端，与手机APP进行数据交互式，将视频列表下发给APP，APP在点击某个视频查看的时候，会报出以下错误，但是视频是可以正常查看的，请问是为什么？

2019-07-25 09:03:33 [Thread: XNIO-1 task-29]-[ERROR]-[io.undertow.servlet.api.LoggingExceptionHandler.handleThrowable()]: UT005023: Exception handling request to /upload/dtxx/19071911/19071911325000001.mp4

java.lang.NullPointerException

at io.undertow.server.handlers.resource.PathResource$1ServerTask.run(PathResource.java:153)

at io.undertow.server.handlers.resource.PathResource.serveImpl(PathResource.java:253)

at io.undertow.server.handlers.resource.PathResource.serveRange(PathResource.java:115)

at io.undertow.servlet.handlers.DefaultServlet.serveFileBlocking(DefaultServlet.java:362)

at io.undertow.servlet.handlers.DefaultServlet.doGet(DefaultServlet.java:201)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:645)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:750)

at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)

at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)

at com.jfinal.core.JFinalFilter.doFilter(JFinalFilter.java:99)

at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)

at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)

at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)

at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)

at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)

at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)

at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)

at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)

at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)

at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)

at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)

at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)

at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)

at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)

at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)

at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)

at io.undertow.servlet.handlers.SessionRestoringHandler.handleRequest(SessionRestoringHandler.java:119)

at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)

at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)

at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)

at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)

at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)

at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)

at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)

at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)

at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)

at io.undertow.server.Connectors.executeRootHandler(Connectors.java:364)

at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830)

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)

at java.lang.Thread.run(Thread.java:748)