Loading JDBC Driver — Class.forName vs Service Loader

Direct Answer

JDBC 4 drivers normally register through the Java service-provider mechanism when their JAR is available to the relevant class loader. Application code can then call DriverManager.getConnection or, preferably in managed applications, obtain a connection from DataSource. Class.forName was commonly required by older drivers and can still be useful in unusual class-loader/plugin environments.

Code Example

// Just add the driver dependency (e.g. mysql-connector-j) to the build.
// No Class.forName needed — SPI auto-registers the driver.
String url = "jdbc:mysql://localhost:3306/shop";
try (Connection con = DriverManager.getConnection(url, "user", "pass")) {
    System.out.println("connected: " + con.getCatalog());
}

// Legacy (only for very old drivers):
// Class.forName("com.mysql.cj.jdbc.Driver");

The driver's META-INF/services/java.sql.Driver entry lets DriverManager find it automatically.

Common Mistakes & Pitfalls

• Still writing Class.forName: unnecessary since JDBC 4.0 with modern drivers.
• No driver on the classpath: No suitable driver found — add the dependency.
• Wrong driver class name: only matters if you use legacy loading.
• Assuming load = connect: registering a driver doesn't open a connection; getConnection does.