There are times when you want to optimize your Solr index. But what is optimize and why do I care?
Optimize is similar to when you defragment your hard drive. Solr will create a new index removing any deleted documents. It is simply house keeping at its best.
I usually do a commit from the Admin UI, going to the overview tab.
However, sometimes we might want to do it programatically, a good example being when you have a spell checker configured to build the dictionary on optimize. The url to optimize is very simple, here is an example with my localhost, just replace with your Solr
Notice how the # is removed from all REST calls vs when the Admin UI loads.