Here is a code snippet that I have used to read from a CLOB, Oracle 10g instance.

PreparedStatment ps = connection.prepareStatement
("SELECT clobcolumn from clobtable");
ResultSet rs = ps.executeQuery();
while(rs.next())
{
    oracle.sql.CLOB clobValue = (oracle.sql.CLOB)rs.getCLOB(1);
    BufferedReader reader = new BufferedReader(new
    InputStreamReader(clobValue.getAsciiStream()));
    String read = null;
    StringBuffer buffer = new StringBuffer();
    while((read = reader.readLine()) != null )
    {
        buffer.append(read);
    }
}