Solr itself doesn't directly access index files - that is the responsibility of Lucene. That's why you see "lucene" in the class names, not "solr".
To be clear, no Solr user will ever have to read or deserialize a .fdt file. Or any Lucene index file for that matter. If you actually do want to work at the Lucene level (which no one here will recommend), start with the Lucene doc: https://lucene.apache.org/core/documentation.html https://lucene.apache.org/core/5_5_0/index.html For File Formats: https://lucene.apache.org/core/5_5_0/core/org/apache/lucene/codecs/lucene54/package-summary.html#package_description After that you will need to become much more familiar with the Lucene (not Solr) source code. If you want to trace through the code from Solr through Lucene, I suggest you start with Solr unit tests in Eclipse. But none of that will be an appropriate topic for users on this (Solr) list. -- Jack Krupansky On Sun, Mar 6, 2016 at 3:34 PM, Bin Wang <binwang...@gmail.com> wrote: > Hi there, I am interested in understanding all the files in the index > folder. > > here <http://stackoverflow.com/questions/35830426/solr-read-index-files> > is > a stackoverflow question that I have tried however failed. > > Can anyone provide some sample code to help me get started. > > Best regards, > Bin >