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This example implements a Knowledge Graph Navigator that queries DBPedia's SPARQL endpoint to discover relationships between entities. Given a natural-language query, it extracts entity names, resolves them to DBPedia URIs, runs SPARQL queries to find connections, and presents the results. It combines the ner_dbpedia (entity recognition) and semantic_web_apache_jena (SPARQL querying) libraries from earlier chapters.

• Java 11+
• Maven 3.6+
• You must build and install these local dependencies first:

cd ../ner_dbpedia && make install
cd ../semantic_web_apache_jena && make install

Note: This example must be run as a JUnit test (or from an IDE), not via mvn exec:java. This is because mvn exec uses a limited classpath that prevents the ner_dbpedia dependency from loading its bundled entity-name data files.

# Install and run via JUnit
make install
mvn test

This example is released using the Apache 2 license.

Copyright 2022-2026 Mark Watson. All rights reserved.

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