Trying to call a processService type method (processAuthentication) on a subclass(org.greenstone.gsdl3.service.Authentication), but an exception happened:java.lang.reflect.InvocationTargetException java.lang.reflect.InvocationTargetException at sun.reflect.GeneratedMethodAccessor7181.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.greenstone.gsdl3.service.ServiceRack.process(ServiceRack.java:318) at org.greenstone.gsdl3.core.MessageRouter.process(MessageRouter.java:325) at org.greenstone.gsdl3.action.GeneralAction.process(GeneralAction.java:120) at org.greenstone.gsdl3.core.Receptionist.process(Receptionist.java:262) at org.greenstone.gsdl3.LibraryServlet.doGetOrPost(LibraryServlet.java:818) at org.greenstone.gsdl3.LibraryServlet.doGet(LibraryServlet.java:847) at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.greenstone.gsdl3.core.URLFilter.doFilter(URLFilter.java:493) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:493) at org.apache.catalina.valves.RequestFilterValve.process(RequestFilterValve.java:348) at org.apache.catalina.valves.RemoteAddrValve.invoke(RemoteAddrValve.java:52) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:650) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) at org.apache.coyote.ajp.AjpProcessor.service(AjpProcessor.java:479) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Unknown Source) Caused by: java.lang.NullPointerException at org.greenstone.gsdl3.util.DerbyWrapper.closeDatabase(DerbyWrapper.java:152) at org.greenstone.gsdl3.service.Authentication.checkAdminUserExists(Authentication.java:1070) at org.greenstone.gsdl3.service.Authentication.processAuthentication(Authentication.java:536) ... 38 more <request lang="ca" remoteAddress="52.14.8.34" to="Authentication" type="process"><userContext lang="ca" uid="A0A74EA5FEA1F3E03AF11B20623A0E12" username="" /><paramList><param name="authpage" value="ListUsers" /></paramList></request> null null admin@example.com https://ibdigital.uib.es/greenstone/library?l=ca https://ibdigital.uib.es