When a polymorphic search is performed HQLQueryPlan.performList() never return any results because there is a mistake in this code: for ( int x = 0; x < size; x++ ) { final Object result = tmp.get( x ); if ( distinction.add( result ) ) { continue; } includedCount++; if ( includedCount < first ) { continue; } } combinedResults.add( result ); if ( max >= 0 && includedCount > max ) { // break the outer loop !!! break translator_loop; } } The call to distinction.add( result ) returns true when the result is added and false when the result is already in the set. So the if code should be: if ( !distinction.add( result ) ) { continue; }