类加载顺序

public class Father {
    static {
        System.out.println("fa static ");
    }

    {
        System.out.println("fa {} ");
    }

    public Father() {
        System.out.println("fa () ");
    }
}

public class Sub extends Father{
    static {
        System.out.println("sub static ");
    }

    {
        System.out.println("sub {} ");
    }

    public Sub() {
        System.out.println("sub () ");
    }
}

fa static
sub static
fa {}
fa ()
sub {}
sub ()