// create a default import and wire it up to the system contribution
// model resolver. This is the trick that makes the resolution processing
// skip over to the system contribution if resolution is unsuccessful
// in the current contribution
DefaultImport defaultImport = contributionFactory.createDefaultImport();
defaultImport.setModelResolver(systemContribution.getModelResolver());
contribution.getImports().add(defaultImport);
}
ExtensibleModelResolver modelResolver = new ExtensibleModelResolver(new Contributions(contributions), modelResolvers, modelFactories);