Solr allows loading plugins by defining <lib/> directives in solrconfig.xml.
The plugins are loaded in the order they appear in solrconfig.xml. If there are dependencies, list the lowest level dependency jar first.
Regular expressions can be used to provide control loading jars with dependencies on other jars in the same directory. All directories are resolved as relative to the Solr instanceDir.
<lib dir="../../../contrib/extraction/lib" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-cell-\d.*\.jar" />
<lib dir="../../../contrib/clustering/lib/" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-clustering-\d.*\.jar" />
<lib dir="../../../contrib/langid/lib/" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-langid-\d.*\.jar" />
<lib dir="../../../contrib/velocity/lib" regex=".*\.jar" />
<lib dir="../../../dist/" regex="solr-velocity-\d.*\.jar" />