Solr is a standalone enterprise search server with a REST-like API. You put documents in it (called indexing) via JSON, XML, CSV or binary over HTTP. You query it via HTTP GET and receive JSON, XML, CSV or binary results.
The following are the things covered under Solr.
Enabling location-based search is simple with Solr's built-in support for spatial search
Solr ships with optional plugins for indexing rich content (e.g. PDFs, Word), language detection, search results clustering and more
Slice and dice your data as you see fit using a large array of faceting algorithms
Fine-grained controls on Solr's built-in caches make it easy to optimize performance
Secure Solr with SSL, Authentication and Role based Authorization. Pluggable, of course!
Solr supports multi-tenant architectures, making it easy to isolate users and content.
The following are the course contents offered for Apache Solr
Download Apache Solr course plan