public byte getByte(String columnName) throws SQLException {
        return getByte(findColumn(columnName));
    }
Gets the value of the designated column in the current row
of this rowset's <code>ResultSet</code> object as
a <code>byte</code>.

@param columnName the SQL name of the column
@return the column value; if the value is SQL <code>NULL</code>, the
value returned is <code>0</code>
@throws SQLException if (1) a database access error occurs
           or (2) this rowset does not have a currently valid connection,
           prepared statement, and result set
src/main/java/org/replicadb/rowset/sun/rowset/JdbcRowSetImpl.java