Where does Lucene store the index it builds?
Typically, the index is stored in a set of files that Lucene creates in a directory of your choice. If your system uses multiple independent indices, simply create a separate directory for each index. Lucene’s API also provide a way to use or implement other storage methods such as a in-memory storage (RAMDirectory), or a mapping of Lucene data to any third party database (not included in Lucene).
