That implies you have a feature doesn't have a type. Likely you have some problem with proxies that fail to resolve so you the resulting Ecore model simply doesn't work until that's addressed.
EObject sourceModel = null; XMIResourceFactoryImpl _xmiFac = new XMIResourceFactoryImpl(); ResourceSet rSet = new ResourceSetImpl(); rSet.getResourceFactoryRegistry().getExtensionToFactoryMap() .put("*", _xmiFac); URI uri = URI.createFileURI(sourceModelFile.getAbsolutePath()); Resource resource = rSet.getResource(uri, true); if (resource != null) { if (resource.getContents().size() > 0) { sourceModel = (EObject) resource.getContents().get(0); } }