Ask about the question of solr cache

[JiaoyanChen]

When I have delete or add data by application through solrj, or have
import index through command nutch solrindex, the cache of solr are not
changed if I do not restart solr.
Could anyone tell me how could I update solr cache without restarting
using shell command?
When I recreate the index by nutch, I should update data in solr. 
I use java -jar start.jar to publish solr.
Thanks!