There is a strange problem I noticed in a JCL that is running in production. There are few datasets that are created in the job but there is no delete step coded in the JCL.
When the Job is rerun it does not give any error indicating that the dataset already exists for those that are cataloged in the jcl.
I really do not understand this. But I notice that there is some UCC step at the start of the job.

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As you noticed UCC11 utility is used in your job and it takes care of deleting any datasets that
are already created and the jcl does not give file exist error
The following statement is coded just after the job statement
//UCC11 EXEC UCC11,RUNTYPE=P
All the datasets with DISP=(NEW,CATLG,DELETE) will be deleted automatically if they already exist and the jcl will not give any issues
Hope this answers your queries.