Construct an Object of type determined at runtime?

So I'm trying to test the methods on a certain class (with a default constructor), and the test methods can only be public and of type void, and must start with "test".

public static void main(String[] args) throws ClassNotFoundException {
    Class<?> c = null;
    c = Class.forName(args[0]);

    System.out.println(c.getName());
    for (Method m : c.getMethods()) {
        if (m.getName().startsWith("test")
                && m.getReturnType().equals(Void.TYPE)
                && m.getModifiers() == Modifier.PUBLIC) {

            Object o = null;

            try {
                o = c.newInstance();
            } catch (InstantiationException | IllegalAccessException ex) {
                System.out.println(ex.getMessage());
            }

            // ???    
        }
    }
}

So, my checks work, but I do not know how to make a new instance of the class and test the method. How would I do this?