HikariCP is a high-performance JDBC connection pool library used in Java applications. It’s part of the ecosystem for managing database connections efficiently and is especially popular in Spring Boot applications.
🔹 What is a Connection Pool?
A connection pool is a cache of database connections maintained so they can be reused, rather than opened and closed repeatedly. Creating a new DB connection is expensive, so pooling helps performance.
🔹 What is HikariCP?
- HikariCP (Hikari Connection Pool) is a JDBC connection pooling library known for:
- Speed: Extremely fast — one of the fastest connection pools available.
- Lightweight: Minimal footprint and configuration.
- Reliability: Designed with simplicity and performance in mind.
🔹 Why and When is it Used?
In Java applications, especially web apps, multiple threads (e.g., HTTP requests) need access to the database. Creating and destroying connections per request would be slow and resource-heavy. HikariCP:
- Reuses existing connections.
- Limits the number of simultaneous DB connections.
- Manages connection lifecycle (e.g., timeouts, idle checks).
- Avoids memory leaks from unclosed connections.
🔹 Use in Java Projects
It’s commonly used with:
- Spring Boot (default connection pool from version 2.0+)
- Hibernate / JPA
- Play Framework
- Any JDBC-based app
Example configuration in application.properties for Spring Boot:
spring.datasource.hikari.maximum-pool-size=10
spring.datasource.hikari.connection-timeout=30000
🔹 Summary
| Feature | Description |
|---|---|
| Purpose | Efficient DB connection pooling |
| Performance | One of the fastest JDBC pools available |
| Integration | Works with Spring Boot, JDBC, JPA, etc. |
| Configuration | Simple and flexible |