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A Baffling Nullpointerexception

Wed, 04/04/2007 - 01:14 — fancychou

These errors happened who can help me?

16:31:35.078 WARN!! Exception for /app?serviceId=Echo.Synchronize
java.lang.NullPointerException
    at nextapp.echo2.webcontainer.syncpeer.ListComponentPeer$RenderedModelData.<init>(ListComponentPeer.java:153)
    at nextapp.echo2.webcontainer.syncpeer.ListComponentPeer$RenderedModelData.<init>(ListComponentPeer.java:121)
    at nextapp.echo2.webcontainer.syncpeer.ListComponentPeer.renderContent(ListComponentPeer.java:386)
    at nextapp.echo2.webcontainer.syncpeer.ListComponentPeer.renderInitDirective(ListComponentPeer.java:443)
    at nextapp.echo2.webcontainer.syncpeer.ListComponentPeer.renderAdd(ListComponentPeer.java:348)
    at nextapp.echo2.webcontainer.syncpeer.RowPeer.renderAddChild(RowPeer.java:172)
    at nextapp.echo2.webcontainer.syncpeer.RowPeer.renderChild(RowPeer.java:268)
    at nextapp.echo2.webcontainer.syncpeer.RowPeer.renderHtml(RowPeer.java:323)
    at nextapp.echo2.webcontainer.syncpeer.RowPeer.renderAddChild(RowPeer.java:170)
    at nextapp.echo2.webcontainer.syncpeer.RowPeer.renderChild(RowPeer.java:268)
    at nextapp.echo2.webcontainer.syncpeer.RowPeer.renderHtml(RowPeer.java:323)
    at nextapp.echo2.webcontainer.syncpeer.ColumnPeer.renderAddChild(ColumnPeer.java:168)
    at nextapp.echo2.webcontainer.syncpeer.ColumnPeer.renderChild(ColumnPeer.java:265)
    at nextapp.echo2.webcontainer.syncpeer.ColumnPeer.renderHtml(ColumnPeer.java:303)
    at nextapp.echo2.webcontainer.syncpeer.ContentPanePeer.renderChild(ContentPanePeer.java:235)
    at nextapp.echo2.webcontainer.syncpeer.ContentPanePeer.renderHtml(ContentPanePeer.java:301)
    at nextapp.echo2.webcontainer.syncpeer.ContentPanePeer.renderAdd(ContentPanePeer.java:165)
    at nextapp.echo2.webcontainer.syncpeer.WindowPeer.renderRefresh(WindowPeer.java:124)
    at nextapp.echo2.webcontainer.syncpeer.WindowPeer.renderUpdate(WindowPeer.java:143)
    at nextapp.echo2.webcontainer.ContainerSynchronizeService.processServerUpdates(ContainerSynchronizeService.java:391)
    at nextapp.echo2.webcontainer.ContainerSynchronizeService.renderUpdate(ContainerSynchronizeService.java:475)
    at nextapp.echo2.webrender.service.SynchronizeService.service(SynchronizeService.java:279)
    at nextapp.echo2.webrender.WebRenderServlet.process(WebRenderServlet.java:273)
    at nextapp.echo2.webrender.WebRenderServlet.doPost(WebRenderServlet.java:189)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:356)
    at org.mortbay.jetty.servlet.WebApplicationHandler.dispatch(WebApplicationHandler.java:294)
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:567)
    at org.mortbay.http.HttpContext.handle(HttpContext.java:1776)
    at org.mortbay.jetty.servlet.WebApplicationContext.handle(WebApplicationContext.java:514)
    at org.mortbay.http.HttpContext.handle(HttpContext.java:1726)
    at org.mortbay.http.HttpServer.service(HttpServer.java:879)
    at org.mortbay.http.HttpConnection.service(HttpConnection.java:790)
    at org.mortbay.http.HttpConnection.handleNext(HttpConnection.java:952)
    at org.mortbay.http.HttpConnection.handle(HttpConnection.java:807)
    at org.mortbay.http.SocketListener.handleConnection(SocketListener.java:196)
    at nextapp.es2.server.PrivateSocketListener.handleConnection(PrivateSocketListener.java:21)
    at org.mortbay.util.ThreadedServer.handle(ThreadedServer.java:289)
    at org.mortbay.util.ThreadPool$PoolThread.run(ThreadPool.java:487)

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Wed, 04/04/2007 - 01:20 — mjablonski
mjablonski's picture

Hi,

seems to be that your feeding a "null" into a ListModel which cannot be rendered by the component peer. Please have a look at your ListModel-Implementation and remove nulls or translate them to something meaningful.

Or use a ListCellRenderer and set it to your ListBox which handles null-objects like:

public class NullableListCellRenderer implements ListCellRenderer {
       public Object getListCellRendererComponent(Component list, Object value,
                   int index) {  
          return value!=null ? value : "";     
       }
}

HTH, Maik

Wed, 02/03/2010 - 19:32 — CCronaldo

Thank you, very

Thank you, very helpful
---------------------------------------
quang cao online | quang cao

Wed, 04/04/2007 - 02:11 — fancychou

Yes, just as you say, Thanks a lot Maik!

Wed, 02/03/2010 - 10:09 — padma

Thank you, very helpful

Thank you, very helpful