ResultSeg.getString Error

I have an error with a getString method of ResultSet

The code is similar like these:

// Made a call of a stored procedure.
int fieldNum = 1;
CallableStatement cstmt =
this.dbConnection.prepareCall( sentenceSQL );
if( cstmt.execute() ){
resultSP = cstmt.getResultSet();
// and there the problem appears, when i get the string of resultset some times sometimes it was cuting information, the database info was incomplete
String fieldValue = resultSP.getString( fieldNum
);
}

I now that these problem present in past, but i dont now how resolve. I need some help.

Carlos