It is also possible to access the CMMN model instance by the case definition id using the Repository Service, as the following incomplete test sample code shows.

    1. public void testRepositoryService() {
    2.   String caseDefinitionId = repositoryService.createCaseDefinitionQuery()
    3.     .caseDefinitionKey(CASE_KEY).singleResult().getId();
    4.   CmmnModelInstance modelInstance = repositoryService
    5.     .getCmmnModelInstance(caseDefinitionId);
    6. }

    原文: https://docs.camunda.org/manual/7.9/user-guide/model-api/cmmn-model-api/repository-service/