Web / Apache Lucene Interview questions
What is Apache Lucene?
Apache Lucene is a free, open-source Java library for full-text indexing and search - not a standalone server. It gives developers the building blocks (indexing, tokenizing, scoring, retrieval) needed to add search to an application, but you embed it directly in code rather than talking to it over HTTP.
Its core job is turning unstructured text into an inverted index so that queries against millions of documents return in milliseconds. Popular search platforms like Elasticsearch and Apache Solr are actually built on top of Lucene - they add distribution, REST APIs, and cluster management around Lucene's core engine.
Typical use cases include site search, log analysis, e-commerce product search, and any feature that needs relevance-ranked text retrieval rather than exact-match database lookups.
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