How JAVA11 use SPI to load SQL Driver Class-CodePudding

In Java8 there is a static block in java.sql.DriverManger class as

    static {
        loadInitialDrivers();
        println("JDBC DriverManager initialized");
    }

It will be executed when java.sql.DriverManger class is loaded by ClassLoader, and it will call the ServiceLoader.load() method to start to scan files under META-IFO/services folder in jars under the classpath. In this way it register all the Driver class defined in services folder.
However, in Java11, it don't have this static block anymore, I was wondering how Java11 starts the SPI process. Thanks for any answers.

CodePudding user response：

In Java 11 the scanning for the drivers is only started when the first connection is opened:

DriverManager.getConnection(String url)

public static Connection getConnection(String url)
    throws SQLException {

    java.util.Properties info = new java.util.Properties();
    return (getConnection(url, info, Reflection.getCallerClass()));
}

calls DriverManager.getConnection(String url, Properties info, Class<?> caller):

private static Connection getConnection(
    String url, java.util.Properties info, Class<?> caller) throws SQLException {
    // [..]
    ensureDriversInitialized();
    // [..]
}

which in turn calls DriverManager.ensureDriversInitialized() which finally uses the java.util.ServiceLoader class to effectively load the drivers:

private static void ensureDriversInitialized() {
    // [..]
                    ServiceLoader<Driver> loadedDrivers = ServiceLoader.load(Driver.class);
    // [..]
}