Solving "Error initializing QueryElevationComponent." with Solr

You may be getting the following error message when trying to start up Solr:

ERROR - 2014-08-11 16:49:49.554; org.apache.solr.core.CoreContainer; Unable to create core: collection1
org.apache.solr.common.SolrException: Error initializing QueryElevationComponent.
        at org.apache.solr.core.SolrCore.<init>(SolrCore.java:868)
        at org.apache.solr.core.SolrCore.<init>(SolrCore.java:643)
        at org.apache.solr.core.CoreContainer.create(CoreContainer.java:556)
        at org.apache.solr.core.CoreContainer$1.call(CoreContainer.java:261)
        at org.apache.solr.core.CoreContainer$1.call(CoreContainer.java:253)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.solr.common.SolrException: Error initializing QueryElevationComponent.
        at org.apache.solr.handler.component.QueryElevationComponent.inform(QueryElevationComponent.java:251)
        at org.apache.solr.core.SolrResourceLoader.inform(SolrResourceLoader.java:651)
        at org.apache.solr.core.SolrCore.<init>(SolrCore.java:851)
        ... 10 more

If you're getting this error, you may have changed your primary index from a string to an int.

To fix this, edit your example/solr/collection1/conf/elevate.xml file, and change it to the following:

<?xml version="1.0" encoding="UTF-8" ?>

<!-- ... -->

<elevate>

 <query text="foo bar">

<!--

  <doc id="1" />

  <doc id="2" />

  <doc id="3" />

-->

 </query>

 <query text="ipod">

<!--   <doc id="MA147LL/A" />  

   <doc id="IW-02" exclude="true" />

-->

 </query>

</elevate>

Specifically, comment out the <doc ... /> tags.