I found that if you have a custom model, a copy of it exists in the alf_data/solr4/model directory.
Mine was zero length. I replaced it with a good copy and I am not getting that error.
However Alfresco is still not starting.
If gets to this point in the log (catalina.out) and stops:
INFO: Starting ProtocolHandler ["http-apr-8080"]
May 02, 2016 10:36:53 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["ajp-apr-8009"]
May 02, 2016 10:36:53 AM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-bio-8443"]
May 02, 2016 10:36:53 AM org.apache.catalina.startup.Catalina start
INFO: Server startup in 64305 ms
2016-05-02 10:38:00,113 WARN [alfresco.util.OpenOfficeConnectionTester] [DefaultScheduler_Worker-6] Error trying to query Open Office version information. OpenOffice.org's ConfigurationRegistry not implemented in this version of OOo. This should not affect the operation of OOo.
2016-05-02 10:38:00,113 INFO [alfresco.util.OpenOfficeConnectionTester] [DefaultScheduler_Worker-6] The OpenOffice connection was re-established.
2016-05-02 10:38:23,730 INFO [solr.component.AsyncBuildSuggestComponent] [Suggestor-alfresco-1] Loaded suggester shingleBasedSuggestions, took 90759 ms
2016-05-02 10:38:30,032 INFO [management.subsystems.ChildApplicationContextFactory] [http-bio-8443-exec-9] Starting 'Transformers' subsystem, ID: [Transformers, default]
2016-05-02 10:38:30,216 INFO [management.subsystems.ChildApplicationContextFactory] [http-bio-8443-exec-9] Startup of 'Transformers' subsystem, ID: [Transformers, default] complete
The solr.log has this error:
2016-05-02 10:34:41,548 ERROR [org.apache.solr.core.SolrCore] java.lang.NullPointerException
at org.alfresco.solr.AlfrescoSolrCloseHook.preClose(AlfrescoSolrCloseHook.java:71)
at org.apache.solr.core.SolrCore.close(SolrCore.java:1046)
at org.apache.solr.core.SolrCores.close(SolrCores.java:117)
at org.apache.solr.core.CoreContainer.shutdown(CoreContainer.java:347)
at org.apache.solr.servlet.SolrDispatchFilter.destroy(SolrDispatchFilter.java:200)
at org.apache.catalina.core.ApplicationFilterConfig.release(ApplicationFilterConfig.java:313)
at org.apache.catalina.core.StandardContext.filterStop(StandardContext.java:4890)
at org.apache.catalina.core.StandardContext.stopInternal(StandardContext.java:5711)
at org.apache.catalina.util.LifecycleBase.stop(LifecycleBase.java:232)
at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1591)
at org.apache.catalina.core.ContainerBase$StopChild.call(ContainerBase.java:1580)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)