import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.List;

public class InvokeDefault {

    public static <T> void invokeDefault (String className, String method) throws ClassNotFoundException, InvocationTargetException, IllegalAccessException, NoSuchMethodException, InstantiationException {
        Class<?> clazz = Class.forName(className);
        Method methodToInvoke = null;
        boolean isMethodFound = false;

        //only works if no-parameter constructor exists, other option not implemented
        Object dummy = clazz.getDeclaredConstructor().newInstance();

        Method[] declaredMethods = clazz.getDeclaredMethods();

        for(Method declaredMethod : declaredMethods){
            if (declaredMethod.getName().equals(method)){
                declaredMethod.setAccessible(true);
                isMethodFound = true;
                methodToInvoke = declaredMethod;
                break;
            }
        }

        if(!isMethodFound){
            for (Method declaredMethod : declaredMethods){
                if (declaredMethod.getName().equals("defaultMethod")){
                    methodToInvoke = declaredMethod;
                }
            }
        }

        List<Parameter> defaultParameters = new ArrayList<>();

        if(isMethodFound){
            Parameter[] parameters = methodToInvoke.getParameters();
            for (Parameter parameter : parameters){
                if (!parameter.getType().isPrimitive()){
                    Method[] objectMethods = parameter.getType().getDeclaredMethods();
                    for (Method objectMethod : objectMethods){
                        if (objectMethod.getName().equals("getDefaultValue") && Modifier.isStatic(objectMethod.getModifiers())){
                            objectMethod.setAccessible(true);
                            defaultParameters.add((Parameter) objectMethod.invoke(parameter.getClass()));
                        }

                        else {
                            defaultParameters.add(null);
                        }
                    }
                }
            }
        }

        if (methodToInvoke != null){
            methodToInvoke.invoke(dummy, defaultParameters.toArray());
        }
    }
}