KML request + legend generation may trigger an exception

java.lang.IllegalArgumentException: Argument "value" should not be null.
        at org.geotools.util.SoftValueHashMap.ensureNotNull(SoftValueHashMap.jav
a:103)
        at org.geotools.util.SoftValueHashMap.put(SoftValueHashMap.java:226)
        at org.geotools.renderer.style.SLDStyleFactory.createStyle(SLDStyleFacto
ry.java:308)
        at org.vfny.geoserver.wms.responses.DefaultRasterLegendProducer.produceL
egendGraphic(DefaultRasterLegendProducer.java:240)
        at org.vfny.geoserver.wms.responses.GetLegendGraphicResponse.execute(Get
LegendGraphicResponse.java:81)
        at org.geoserver.ows.adapters.ResponseAdapter.getMimeType(ResponseAdapte
r.java:48)
        at org.geoserver.ows.Dispatcher.response(Dispatcher.java:585)
        at org.geoserver.ows.Dispatcher.handleRequestInternal(Dispatcher.java:19
1)
        at org.springframework.web.servlet.mvc.AbstractController.handleRequest(
AbstractController.java:139)
        at org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter.ha
ndle(SimpleControllerHandlerAdapter.java:44)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(Dispatch
erServlet.java:684)
        at org.springframework.web.servlet.DispatcherServlet.doService(Dispatche
rServlet.java:625)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(Frame
workServlet.java:392)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServl
et.java:347)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
        at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:459
)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(Servlet
Handler.java:1054)
        at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(F
ilterChainProxy.java:264)
        at org.acegisecurity.intercept.web.FilterSecurityInterceptor.invoke(Filt
erSecurityInterceptor.java:107)
        at org.acegisecurity.intercept.web.FilterSecurityInterceptor.doFilter(Fi
lterSecurityInterceptor.java:72)
        at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(F
ilterChainProxy.java:274)
        at org.acegisecurity.ui.ExceptionTranslationFilter.doFilter(ExceptionTra
nslationFilter.java:110)
        at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(F
ilterChainProxy.java:274)
        at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFil
ter(AnonymousProcessingFilter.java:125)
        at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(F
ilterChainProxy.java:274)
        at org.acegisecurity.ui.basicauth.BasicProcessingFilter.doFilter(BasicPr
ocessingFilter.java:178)
        at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(F
ilterChainProxy.java:274)
        at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilte
r(HttpSessionContextIntegrationFilter.java:229)
        at org.acegisecurity.util.FilterChainProxy$VirtualFilterChain.doFilter(F
ilterChainProxy.java:274)
        at org.acegisecurity.util.FilterChainProxy.doFilter(FilterChainProxy.jav
a:148)
        at org.acegisecurity.util.FilterToBeanProxy.doFilter(FilterToBeanProxy.j
ava:98)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(Servlet
Handler.java:1045)
        at org.vfny.geoserver.filters.SetCharacterEncodingFilter.doFilter(SetCha
racterEncodingFilter.java:108)
        at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(Servlet
Handler.java:1045)
        at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:3
58)
        at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:2
31)
        at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:6
29)
        at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:453)

        at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHand
lerCollection.java:149)
        at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.
java:123)
        at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:1
41)
        at org.mortbay.jetty.Server.handle(Server.java:303)
        at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:45
2)
        at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpCo
nnection.java:721)
        at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:509)
        at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:209)
        at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:349)
        at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.ja
va:320)
        at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool
.java:475)