IllegalArgumentException: wrong number of arguments
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Reflection {

    /**
     * @param args
     * @throws InvocationTargetException
     * @throws IllegalArgumentException
     * @throws IllegalAccessException
     */
    public static void main(String[] args) throws IllegalAccessException,
            InvocationTargetException, IllegalArgumentException {
        Class<Cls> cls = Cls.class;
        Method[] methods = cls.getMethods();
        for (Method m : methods) {
            m.invoke(cls);
        }
    }

}

class Cls {
    public static void method1() {
        System.out.println("Method1");
    }

    public static void method2() {
        System.out.println("Method2");
    }
}

m.invoke(cls, null);