Geoserver GetCapabilites XML error

Question

I have a Geoserver (version 2.5.1) with layers that are assigned to specific users and groups which has been working very well for quite a while. Operationally very little has changed. New users & groups have been added and new layers published and assigned to the groups. Layers for each group are published to a specific group are published to a common workspace. some of the layers use a common style which is published to a shared workspace. For example, a shapefile in Workspace (X) and another published to Workspace (Y) both use a style from Workspace (Z).

This has been working well for about 2 years. Suddenly some users are not able to view any layers. When I checked the GetCapabilites XML it is being truncated at about row 6440. The error points to some error with a specific layer.

<Layer queryable="1" opaque="0">
    <Name>kuilsriver:Kalkfontein BW</Name>
    <Title>Kalkfontein Block Watch</Title>
    <Abstract/>
    <KeywordList>
      <Keyword>features</Keyword>
      <Keyword>Kalkfontein</Keyword>
    </KeywordList>
    <SRS>EPSG:4326</SRS>
    <!--<?xml version="1.0" encoding="UTF-8" standalone="no"?><!DOCTYPE 
    ServiceExceptionReport SYSTEM 

"http://live.webserver.com:80/geoserver/schemas/wms/1.1.1/WMS_exception_1_1_1.dtd"> javax.xml.transform.TransformerException: java.lang.NullPointerException java.lang.NullPointerException null

If I delete the layer the error is repeated for the next alphabetical layer, and so on.

There have been no changes to the server except for adding users, groups, roles and layers so why this error should suddenly occur is unexplained.

I initially thought that the error may be caused something in a recently published layer but after removing all the layers published in the last week (with the corresponding users, groups and roles) the error persists.

I have checked other posts about errors in the GetCapabilites XML but resolution suggestions have not solved my problem.

Answer 1

Typically, that happens when a particular layer is left without a default style (should not happen, and there is afaik no step by step reproducible way to make it happen).

Suggestion: go to the global setting and set the service error setting to "skipping misconfigured layers":

The caps should generate again, logging an error, and hopefully looking at it you'll find which layer failed.