Any other methods can replace crontab?

Hi expert,
I wrote a simple shell to start LTOM in background task mode, it was OK when started manually, but failed by crontab.
The error message in log is:
Exception in thread "main" java.lang.NoClassDefFoundError: sun.misc.BASE64Decoder
   at LTOM.StringEncrypter.decrypt(StringEncrypter.java:125)
   at LTOM.Ltom.main(Ltom.java:1024)

The area of the code where this is coming from is encrypting the password.
BUT I started the shell ok by manual.

manual start: sh /home/oracle/ltom/bktask.sh
crontab: 0,10,20,30,40,50 * * * * sh /home/oracle/ltom/bktask.sh

Following is my script:

bktask.sh

#!/bin/sh

#set env