Need help on the java udf

Hi

Here id the soruce strucre

Target -  I need to map it to Reference qualifer 1:Unbounded

z1EKPD1 can occur muliple times in one item

If zzontractnumber not eual to blank  then

     if substring(ZZPARSRATING(0,2) = DS then

          copy DS

               else

          if substring(ZZPARSRATING(0,2)= DX then

          copy DX

If the value of zzparsrating existing in all the line  items it is working but it it has only in 2nd item i am getting arryindexout of bound exception and not populating the value of zzparsrating

and if the Z1EKPD1 has more than one then also i am getting exception

Thanks for your help