java.io.IOException: Not in GZIP format
        at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:137)
        at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:58)
        at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:68)
        at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogParser.getInputSource(AutoupdateCatalogParser.java:180)
        at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogParser.getUpdateItems(AutoupdateCatalogParser.java:150)
        at org.netbeans.modules.autoupdate.updateprovider.AutoupdateCatalogProvider.getUpdateItems(AutoupdateCatalogProvider.java:110)
        at org.netbeans.modules.autoupdate.services.UpdateUnitFactory.appendUpdateItems(UpdateUnitFactory.java:170)
        at org.netbeans.modules.autoupdate.services.UpdateUnitFactory.getUpdateUnits(UpdateUnitFactory.java:140)
        at org.netbeans.modules.autoupdate.services.UpdateManagerImpl$Cache.<init>(UpdateManagerImpl.java:222)
        at org.netbeans.modules.autoupdate.services.UpdateManagerImpl.getCache(UpdateManagerImpl.java:196)
        at org.netbeans.modules.autoupdate.services.UpdateManagerImpl.getUpdateUnits(UpdateManagerImpl.java:93)
        at org.netbeans.api.autoupdate.UpdateManager.getUpdateUnits(UpdateManager.java:100)
        at org.netbeans.modules.autoupdate.pluginimporter.PluginImporter.inspect(PluginImporter.java:112)
        at org.netbeans.modules.autoupdate.pluginimporter.PluginImporter.getInstalledPlugins(PluginImporter.java:186)
        at org.netbeans.modules.autoupdate.pluginimporter.Installer$2.run(Installer.java:148)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:573)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1005)