code: protected void removeExecutionLink(JobEntity jobEntity) {
          if (jobEntity.getExecutionId() != null) {
              ExecutionEntity execution = getExecutionEntityManager().findById(jobEntity.getExecutionId());
              if (execution != null) {
                  execution.getJobs().remove(jobEntity);
              }
          }
      }
docs: Removes the job's execution's reference to this job, if the job has an associated execution.
  Subclasses may override to provide custom implementations.