IdentifierProjection does not work with composite keys ------------------------------------------------------ Key: HHH-1088 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-1088 Project: Hibernate Core Issue Type: Bug Components: query-criteria Affects Versions: 3.1 rc2 Reporter: Max Muermann Attachments: CompositeIdProjection.java, CriteriaLoader.java When working with Criteria queries, the IdentifierProjection breaks if the entity has a composite key. In IdentifierProjection.java: public String toSqlString(Criteria criteria, int position, CriteriaQuery criteriaQuery) throws HibernateException { StringBuffer buf = new StringBuffer(); String[] cols = criteriaQuery.getIdentifierColumns(criteria); for ( int i=0; i<cols.length; i++ ) { buf.append( cols[i] ) .append(" as y") .append(position + i) .append('_'); } return buf.toString(); } This method does not add commas as separators between the column names. Easily fixed by adding if (i<col.length-1) buf.append(","); as the last statement inside the loop. However, this leads to another problem: the type returned by IdentifierProjection.geType is the (single) type of the composite id component. The query will however return the property values of the id component without a mapping step.