Hey Bharath,
I am only another user, but let me tell you at least some things.
First of all, may it be that you forgot the closing square bracket for
"key4"?.
Anyway, if you can comma-separate the records, and put them into an
array, JAQL will definitely be able to read this. (But that is only
the way i know, there may be others)
If alle these records would be in one array, you may access key8 like:
"array[].key4[].key7[].key8" to get all key8 values. For certain
indices you have put numbers into the brackets.
I remember a bug which prevented accessing nested records, but I think
it was fixed some time ago. Go ahead and have a try :).
I hope this was helpful,
Best regards,
Markus