pieces of code doesn't work with oracle

I'm using oracle 10gR2 with helma and "SELECT 1" isn't a valid sql
command in oracle (at least
"SELECT 1 FROM DUAL", so i get a "Connection closed" exception from
time to time while executing
queries...

    public Connection getConnection(DbSource src) {
        Connection con = (Connection) sqlConnections.get(src);
        if (con != null && !testedConnections.contains(src)) {
            // Check if the connection is still alive by executing a
simple statement.
            try {
                Statement stmt = con.createStatement();
                stmt.execute("SELECT 1");
                stmt.close();
                testedConnections.add(src);
            } catch (SQLException sx) {
                try {
                    con.close();
                } catch (SQLException ignore) {/* nothing to do */}
                return null;
            }
        }
        return con;
    }

thanx