Java SE (Java Platform, Standard Edition)

Greetings.

Our product has recently had some Java components added to it.
These components require that the JRE be installed on the target
computer (Windows) along with the rest of our product. We would
like to perform JRE installation automatically as part of normal product
installation. Most of our users are not technical, e.g., they do not know
how to navigate the file system..

Our product installer is built with Installshield. I'm looking for advice
on the best way to incorporate JRE installion into our existing product
installation process. Also, recommendations on whether to use the
network or offline JRE installer and why?

I tried launching the JRE Offline installer .exe from my MSI installer
(put the JRE .exe into the binary table, added a custom action to
execute it). I get an error "Error 1500, another installation is in progress".