This chapter contains an approach to spell out the similarities and the differences between the JES3 user exits you might be running and how they could be implemented into JES2 exits.
8.1 JES3 user exits
Table on page 113
contains a list of all the JES3-provided user exits and a brief description of the purpose of the exit.
The first step is to identify if you are using the exit or not. Some exits might be written by your installation, others might be provided by products that need to communicate with or monitor JES3: a batch job ...