Install Hippo CMS : NullPointerException with essentials webapp

I followed these instructions (Hippo CMS installation instructions) to install Hippo CMS 7.

I followed :

Step 1 : run Maven archetype locally
Step 2 : compile & package locally with Maven
I did not followed step 3 instruction, as I build the WAR files (cms.war, essentials.war and site.war) on my Windows 8.1 / Oracle JDK 8 / Maven 3.3 locally and transfer generated WAR files on a Debian 7 / Oracle JDK 8 / Tomcat 8 / no Maven server

What I get :

http://{myserver}:{myport}/cms is working perfectly
http://{myserver}:{myport}/console is working perfectly
http://{myserver}:{myport}/site is working perfectly
http://{myserver}:{myport}/essentials give a HTTP 500 error code (but WAR is correctly deployed and launched)

Stack trace :

08-Apr-2015 19:39:55.565 SEVERE [http-nio-8080-exec-6] org.apache.catalina.core.StandardWrapperValve.invoke "Servlet.service()" pour la servlet REST a généré une exception
 java.lang.RuntimeException: org.apache.cxf.interceptor.Fault
        at org.apache.cxf.interceptor.AbstractFaultChainInitiatorObserver.onMessage(AbstractFaultChainInitiatorObserver.java:116)
        at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:324)
        at org.apache.cxf.transport.ChainInitiationObserver.onMessage(ChainInitiationObserver.java:121)
        at org.apache.cxf.transport.http.AbstractHTTPDestination.invoke(AbstractHTTPDestination.java:237)
        at org.apache.cxf.transport.servlet.ServletController.invokeDestination(ServletController.java:239)
        at org.apache.cxf.transport.servlet.ServletController.invoke(ServletController.java:213)
        at org.apache.cxf.transport.servlet.CXFNonSpringServlet.invoke(CXFNonSpringServlet.java:131)
        at org.apache.cxf.transport.servlet.AbstractHTTPServlet.handleRequest(AbstractHTTPServlet.java:266)
        at org.apache.cxf.transport.servlet.AbstractHTTPServlet.doGet(AbstractHTTPServlet.java:191)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
        at org.apache.cxf.transport.servlet.AbstractHTTPServlet.service(AbstractHTTPServlet.java:242)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1086)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:659)
        at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1558)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1515)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.cxf.interceptor.Fault
        at org.apache.cxf.service.invoker.AbstractInvoker.createFault(AbstractInvoker.java:162)
        at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:128)
        at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:165)
        at org.apache.cxf.jaxrs.JAXRSInvoker.invoke(JAXRSInvoker.java:89)
        at org.apache.cxf.interceptor.ServiceInvokerInterceptor$1.run(ServiceInvokerInterceptor.java:57)
        at org.apache.cxf.interceptor.ServiceInvokerInterceptor.handleMessage(ServiceInvokerInterceptor.java:93)
        at org.apache.cxf.phase.PhaseInterceptorChain.doIntercept(PhaseInterceptorChain.java:263)
        ... 30 more
**Caused by: java.lang.NullPointerException
        at org.onehippo.cms7.essentials.plugin.PluginStore.getAllPlugins(PluginStore.java:125)
        at org.onehippo.cms7.essentials.rest.PluginResource.getModules(PluginResource.java:290)**
        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:497)
        at org.apache.cxf.service.invoker.AbstractInvoker.performInvocation(AbstractInvoker.java:180)
        at org.apache.cxf.service.invoker.AbstractInvoker.invoke(AbstractInvoker.java:96)
        ... 35 more

It seems that "GET /essentials/rest/plugins" web service is the call generating the exception.

Do you have any idea?

Solution

As described on One Hippo's setup instructions, the setup application is intended for use on the local development host only.

This is because it strongly interacts with your project's files. As such, using it on a remote server doesn't make much sense. Once you leave the development host, don't bother deploying the essentials WAR. (Note how the Hippo project distribution does not include the essentials WAR.)