Adding comment for cohortDefinition.getDetails().getExpression() necessity

Author: Alex Manoylenko

src/main/java/org/ohdsi/webapi/service/CohortGenerationService.java

@@ -111,7 +111,11 @@ public JobExecutionResource generateCohortViaJob(UserEntity userEntity, CohortDe
               .setStartTime(Calendar.getInstance().getTime());
 
       cohortDefinitionRepository.save(cohortDefinition);
-
+      // the line below is essential to access the Cohort definition details in GenerateLocalCohortTasklet.generateCohort
+      // and avoid org.hibernate.LazyInitializationException: 
+      // could not initialize proxy [org.ohdsi.webapi.cohortdefinition.CohortDefinitionDetails#38] - no Session
+      // the workaround doesn't look pure in the same time refactoring doesn't look minor 
+      // as a lot of components are instantiated by the new operator
       cohortDefinition.getDetails().getExpression();
 
       return runGenerateCohortJob(cohortDefinition, source, demographicStat);  }