Getting a caller's class name in Java with SecurityManager.getClassContext()

App.java

public class App {

    public static void main(String[] args) throws Throwable {
        Logger.INSTANCE.log("main() started");
        Logger.INSTANCE.log("hello");
        Logger.INSTANCE.log("main() finished");
    }

    private static class Logger extends SecurityManager {

        public static final Logger INSTANCE = new Logger();

        public void log(String message) {
            Class caller = getClassContext()[1];
            System.out.printf("[%s]: %s%n", caller.getName(), message);
        }
    }
}