Repository Service
It is also possible to access the DMN model instance by the decision definition id using the Repository Service, as the following incomplete test sample code shows:
public void testRepositoryService() {
String decisionDefinitionId = repositoryService.createDecisionDefinitionQuery()
.decisionDefinitionKey(DECISION_KEY).singleResult().getId();
DmnModelInstance modelInstance = repositoryService
.getDmnModelInstance(decisionDefinitionId);
}