#vulnerable code 
                                @Override
    public boolean revert(final HmilyParticipantUndo participantUndo) throws SQLRevertException {
        RevertSQLUnit revertSQLUnit = SQLImageMapperFactory.newInstance(participantUndo.getUndoInvocation()).cast();
        DataSource dataSource = HmilyResourceManager.get(participantUndo.getResourceId()).getTargetDataSource();
        return executeUpdate(revertSQLUnit, dataSource) > 0;
    } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Override
    public boolean revert(final HmilyParticipantUndo participantUndo) throws SQLRevertException {
        try (Connection connection = HmilyResourceManager.get(participantUndo.getResourceId()).getTargetDataSource().getConnection()) {
            return doRevertInTransaction(connection, participantUndo.getUndoInvocation().getTuples());
        } catch (final SQLException ex) {
            log.error("hmily tac rollback exception -> ", ex);
            return false;
        }
    }