"Caused by: solr.TieredMergePolicyFactory"
The reason maybe it failed to load the class and this is because the example solr config file has an error in it:
<mergePolicyFactory class="solr.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="segmentsPerTier">10</int>
</mergePolicyFactory>
This is what worked for me:
<mergePolicyFactory class="org.apache.solr.index.TieredMergePolicyFactory">
<int name="maxMergeAtOnce">10</int>
<int name="segmentsPerTier">10</int>
</mergePolicyFactory>