Load a model .mph using Java

Hi,

I want to knnow how to load a model .mph using Java code,

My goal is to load a model named "mymodel.mph" build in Comsol 4.2, after that I use the Model object in order to resolve equations,

I did...

Model model = ModelUtil.load("Model", "mymodel.mph");

and I find

exception NullPointerException


Thanks in advance