Invoke script depending on previous scripts

Hi,
I am in desperate needs for advice! I have a script which would invoke various java programs depending on the input parameter and a script which would perform calculation on the data inputted by the first script. The schedule of the job is like this

1) 10:00 am to 11:00 am: call java program to insert/update record type A
2) 11:00 am to 2:00 pm: call java program to insert/update record type B
3) 2:00 pm to 4:00 pm: call java program to insert/update recrod type C
4) 12:00 am to 9:00 am: call java program to insert/update record type D
5) 12:00 am to 9:00 am: after step 1/2/3/4 are done, I would to invoke a script to perform calculation.

Could any of you experts help me out?? I AM REALLY REALLY CONFUSED at this point! THANKS!