title: dspace error blank xmlui page
body: <p>I have installed dspace from source on my Ubuntu 16.04 computer.  I followed the steps in the long description here:</p>
  
  <p><a href="https://wiki.duraspace.org/display/DSDOC6x/Installing+DSpace" rel="nofollow noreferrer">https://wiki.duraspace.org/display/DSDOC6x/Installing+DSpace</a></p>
  
  <p>When I try to access the xmlui page, I get a white screen in the browser, and a long list of error messages in the log, below.  I have checked, and in the src directory, Context.java has the method getCurrentMode, which is being called by CommunityBrowser.java on line 150.  I get a nice page when I go to jspui, but this same error appears when I have logged in, although it shows an error message on the page rather than nothing at all, as with xmlui.</p>
  
  <p>Can anyone suggest something?</p>
  
  <pre><code>javax.servlet.ServletException: Servlet execution threw an exception
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:238)
      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.dspace.app.webui.filter.RegisteredOnlyFilter.doFilter(RegisteredOnlyFilter.java:66)
      at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
      at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
      at org.dspace.utils.servlet.DSpaceWebappServletFilter.doFilter(DSpaceWebappServletFilter.java:78)
      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:478)
      at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140)
      at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80)
      at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
      at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87)
      at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342)
      at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:799)
      at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
      at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
      at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1455)
      at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
      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:748)
  
  
  Caused by: java.lang.NoSuchMethodError: org.dspace.core.Context.getCurrentMode()Lorg/dspace/core/Context$Mode;
      at org.dspace.app.xmlui.aspect.artifactbrowser.CommunityBrowser.getValidity(CommunityBrowser.java:150)
      at sun.reflect.GeneratedMethodAccessor128.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at org.apache.cocoon.core.container.spring.avalon.PoolableProxyHandler.invoke(PoolableProxyHandler.java:71)
      at com.sun.proxy.$Proxy402.getValidity(Unknown Source)
      at org.apache.cocoon.components.pipeline.impl.AbstractCachingProcessingPipeline.getValidityForInternalPipeline(AbstractCachingProcessingPipeline.java:987)
      at org.apache.cocoon.components.pipeline.impl.AbstractCachingProcessingPipeline.setupValidities(AbstractCachingProcessingPipeline.java:482)
      at org.apache.cocoon.components.pipeline.impl.AbstractCachingProcessingPipeline.setupPipeline(AbstractCachingProcessingPipeline.java:720)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.preparePipeline(AbstractProcessingPipeline.java:466)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.prepareInternal(AbstractProcessingPipeline.java:480)
      at sun.reflect.GeneratedMethodAccessor127.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at org.apache.cocoon.core.container.spring.avalon.PoolableProxyHandler.invoke(PoolableProxyHandler.java:71)
      at com.sun.proxy.$Proxy396.prepareInternal(Unknown Source)
      at org.apache.cocoon.components.source.impl.SitemapSource.init(SitemapSource.java:292)
      at org.apache.cocoon.components.source.impl.SitemapSource.&lt;init&gt;(SitemapSource.java:148)
      at org.apache.cocoon.components.source.impl.SitemapSourceFactory.getSource(SitemapSourceFactory.java:62)
      at org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:153)
      at org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:183)
      at org.apache.cocoon.generation.FileGenerator.setup(FileGenerator.java:99)
      at org.dspace.app.xmlui.cocoon.AspectGenerator.setup(AspectGenerator.java:81)
      at sun.reflect.GeneratedMethodAccessor118.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at org.apache.cocoon.core.container.spring.avalon.PoolableProxyHandler.invoke(PoolableProxyHandler.java:71)
      at com.sun.proxy.$Proxy397.setup(Unknown Source)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.setupPipeline(AbstractProcessingPipeline.java:343)
      at org.apache.cocoon.components.pipeline.impl.AbstractCachingProcessingPipeline.setupPipeline(AbstractCachingProcessingPipeline.java:710)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.preparePipeline(AbstractProcessingPipeline.java:466)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.prepareInternal(AbstractProcessingPipeline.java:480)
      at sun.reflect.GeneratedMethodAccessor127.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at org.apache.cocoon.core.container.spring.avalon.PoolableProxyHandler.invoke(PoolableProxyHandler.java:71)
      at com.sun.proxy.$Proxy396.prepareInternal(Unknown Source)
      at org.apache.cocoon.components.source.impl.SitemapSource.init(SitemapSource.java:292)
      at org.apache.cocoon.components.source.impl.SitemapSource.&lt;init&gt;(SitemapSource.java:148)
      at org.apache.cocoon.components.source.impl.SitemapSourceFactory.getSource(SitemapSourceFactory.java:62)
      at org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:153)
      at org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:183)
      at org.apache.cocoon.generation.FileGenerator.setup(FileGenerator.java:99)
      at org.dspace.app.xmlui.cocoon.AspectGenerator.setup(AspectGenerator.java:81)
      at sun.reflect.GeneratedMethodAccessor118.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:498)
      at org.apache.cocoon.core.container.spring.avalon.PoolableProxyHandler.invoke(PoolableProxyHandler.java:71)
      at com.sun.proxy.$Proxy397.setup(Unknown Source)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.setupPipeline(AbstractProcessingPipeline.java:343)
      at org.apache.cocoon.components.pipeline.impl.AbstractCachingProcessingPipeline.setupPipeline(AbstractCachingProcessingPipeline.java:710)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.preparePipeline(AbstractProcessingPipeline.java:466)
      at org.apache.cocoon.components.pipeline.AbstractProcessingPipeline.prepareInternal(AbstractProcessingPipeline.java:480)
      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.apache.cocoon.core.container.spring.avalon.PoolableProxyHandler.invoke(PoolableProxyHandler.java:71)
      at com.sun.proxy.$Proxy396.prepareInternal(Unknown Source)
      at org.apache.cocoon.components.source.impl.SitemapSource.init(SitemapSource.java:292)
      at org.apache.cocoon.components.source.impl.SitemapSource.&lt;init&gt;(SitemapSource.java:148)
      at org.apache.cocoon.components.source.impl.SitemapSourceFactory.getSource(SitemapSourceFactory.java:62)
      at org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:153)
      at org.apache.cocoon.components.source.CocoonSourceResolver.resolveURI(CocoonSourceResolver.java:183)
      at org.apache.cocoon.generation.FileGenerator.setup(FileGenerator.java:99)
  </code></pre>
  
  <p>and many more cocoon errors...</p>