JDBC has been around for a long time but because the database interaction happens through higher abstraction API (such as JPA/Hibernate or jOOQ), it’s easy to forget that the actual communication plays by the database driver and the database engine rules. This presentation goes through the most common sources of performance bottlenecks: database connection management, batch updates, statement caching, result set fetching and concurrency control mechanisms with practical references for the most common database systems: Oracle, SQL Server, PostgreSQL and MySQL.