[hibernate-issues] [Hibernate-JIRA] Resolved: (HHH-2463) ClassCastException when Hibernate tries to cache results using ResultTransformer

ClassCastException when Hibernate tries to cache results using ResultTransformer -------------------------------------------------------------------------------- Key: HHH-2463 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-2463 Project: Hibernate3 Issue Type: Bug Affects Versions: 3.2.2 Reporter: Peak user Attachments: ResultTransformerUtil.java When Hibernate executes a cacheable query using a ResultTransformer, it will attempt to cache the results AFTER applying the ResultTransformer. The problem is that the ResultTransformer may modify the data in a way that Hibernate won't understand it anymore, and in this case it will generate a ClassCastException when trying to cache it. This problem could be easily solved if Hibernate cached results before applying the ResultTransformer instead of afterwards. Here's a sample code to reproduce this problem: class ToMapResultTransformer implements ResultTransformer { private String[] properties; public ToMapResultTransformer(String[] properties) { this.properties = properties; } public List transformList(List collection) { return collection; } public Object transformTuple(Object[] tuple, String[] aliases) { Map<String,Object> result = new HashMap<String,Object>(tuple.length); for (int i=0; i<tuple.length; i++) { result.put((properties != null ? properties[i] : aliases[i]), tuple[i]); } return result; } } Criteria sqlCriteria = createSqlCriteria(session); sqlCriteria.setProjection(projections); sqlCriteria.setCacheable(true); sqlCriteria.setResultTransformer(new ToMapResultTransformer(properties)); sqlCriteria.list(); The code above produces the following exception: java.lang.ClassCastException: java.util.HashMap at org.hibernate.cache.StandardQueryCache.put(StandardQueryCache.java:83) at org.hibernate.loader.Loader.putResultInQueryCache(Loader.java:2185) at org.hibernate.loader.Loader.listUsingQueryCache(Loader.java:2129) at org.hibernate.loader.Loader.list(Loader.java:2087) at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:94) at org.hibernate.impl.SessionImpl.list(SessionImpl.java:1569) at org.hibernate.impl.CriteriaImpl.list(CriteriaImpl.java:283)