Q: What is this java.sql.SQLException: ORA-01467: sort key too long?

A: The standard answer is

   Cause:  A DISTINCT, GROUP BY, ORDER BY, or SET operation requires a sort key longer than that 
           supported by Oracle. Either too many columns or too many group functions were specified
           in the SELECT statement.

   Action: Reduce the number of columns or group functions involved in the operation.

   One must realize how and which columns are included in the length calculation.