JDBC Connection URL Format

Direct Answer

Every JDBC URL starts with jdbc:, followed by a driver-specific subprotocol and syntax. There is no universal requirement that it use ://host:port/database. PostgreSQL and MySQL commonly use that network form, while H2, SQLite, Oracle, SQL Server, and vendor data sources use different forms. Follow the selected driver's documentation.

Code Example

// MySQL — note the params after the ? configure SSL + timezone
String mysql = "jdbc:mysql://localhost:3306/shop?useSSL=false&serverTimezone=UTC";
// PostgreSQL — different default port (5432) and its own params
String pg    = "jdbc:postgresql://localhost:5432/shop?sslmode=disable";
// Oracle (thin driver) — uses a SID/service form, not the //host pattern
String ora   = "jdbc:oracle:thin:@localhost:1521:XE";

// DriverManager reads the subprotocol ("mysql") to choose the registered driver
try (Connection con = DriverManager.getConnection(mysql, "user", "pass")) {
    System.out.println("connected to " + con.getCatalog()); // prints: shop
}

The subprotocol (mysql, postgresql, oracle:thin) is the only part that selects the driver — everything else just locates the database.

Common Mistakes & Pitfalls

• Wrong port: MySQL is 3306, PostgreSQL is 5432 — mixing them up means the connection times out.
• Missing required params: MySQL 8 often needs serverTimezone; omitting it throws a timezone error on startup.
• Typo in the subprotocol: jdbc:mysq: matches no registered driver, so you get No suitable driver found.
• Hard-coding credentials in the URL: keep username and password out of source control; pass them separately or via config.
• Forgetting the leading jdbc:: a bare mysql://... is not a JDBC URL and will not be recognised.