same issue in current release "4.3.0.Final" too (not using spring, only hibernate). it´s not possible to read CLOB data from mysql database. if CLOB column is null, reading the data line is possible. as soon as the column includes a value, the following error occurs:

java.lang.IllegalArgumentException: interface org.hibernate.engine.jdbc.WrappedClob is not visible from class loader

Please check this issue as it is not possible to handle CLOB data with current release.