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.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.greenstone.gsdl3.service.ServiceRack.process(ServiceRack.java:323) at org.greenstone.gsdl3.core.MessageRouter.process(MessageRouter.java:331) 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:976) at org.greenstone.gsdl3.LibraryServlet.doGet(LibraryServlet.java:1005) at javax.servlet.http.HttpServlet.service(HttpServlet.java:489) at javax.servlet.http.HttpServlet.service(HttpServlet.java:583) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:212) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156) at org.greenstone.gsdl3.core.URLFilter.doFilter(URLFilter.java:405) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:181) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:156) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:168) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:90) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:483) at org.apache.catalina.valves.rewrite.RewriteValve.invoke(RewriteValve.java:562) at org.apache.catalina.valves.RequestFilterValve.process(RequestFilterValve.java:355) at org.apache.catalina.valves.RemoteAddrValve.invoke(RemoteAddrValve.java:54) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:130) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:93) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:679) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:346) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:617) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:63) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:934) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1698) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52) at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:63) at java.lang.Thread.run(Thread.java:750) Caused by: java.lang.NullPointerException at org.greenstone.gsdl3.util.DerbyWrapper.closeDatabase(DerbyWrapper.java:180) at org.greenstone.gsdl3.service.Authentication.checkAdminUserExists(Authentication.java:1079) at org.greenstone.gsdl3.service.Authentication.processAuthentication(Authentication.java:541) ... 40 more <request lang="en" remoteAddress="10.202.1.11" to="Authentication" type="process"><userContext editEnabled="false" groups="" lang="en" uid="DDFE0E978A33DD411DD805A4B872C3D4" username="" /><paramList><param name="authpage" value="ListUsers" /></paramList></request>