Get started
Loading...
Important Notice - Forums is archived

To simplify things and help our users to be more productive, we have archived the current forum and focus our efforts on helping developers on Stack Overflow. You can post new questions on Stack Overflow or join our Discord channel.

Product icon
TUTORIAL

Vaadin lets you build secure, UX-first PWAs entirely in Java.
Free ebook & tutorial.

Where to include a web components css file when integrating a third party w by Martin Vyšný, 1 week ago
Recent Posts
Vaadin Forum3. Vaadin 6, 7, 8Framework UI

Error using a FileDownloader in a popup window.

Tullio Bettinazzi
5 years ago Sep 01, 2016 11:27am

I try to use a FIleDownloader extension on a button in a popup window.
When I try to use it I get an error :
java.lang.NullPointerException
    at com.vaadin.server.FileDownloader.handleConnectorRequest(FileDownloader.java:134)
    at axioma.web.template.ui.components.DocumentDownloader.handleConnectorRequest(DocumentDownloader.java:24)
    at com.vaadin.server.ConnectorResourceHandler.handleRequest(ConnectorResourceHandler.java:90)
    at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1409)
    at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:364)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

Going deeper I saw the proble comse out because the handleConnectorRequest tryes to get the session using a getSession method which returns null.
The method returns null because it tries to get the UI, using getUI, which returns null.
How van I solve thate issue ?
Is it a bug ?
Tks
Tullio