Windows 7/Windows Server 2008 R2 in ESXi 3.5/ESXi 4

For the love of God, package your app with a local copy of the Java binary if your app needs a specific version. Don't rely on the system-installed binary. This prevents the users from being able to update their Java browser plug-ins.

With the recent major vulnerabilities in Java lately, I'd stop using your product immediately if you told me I couldn't update Java.

That said, if your customers are administrators on these computers, there is nothing you can do to prevent this. Write better code.

If you're having a problem with a Dell server, use the Dell ESXi image, as it had the agents and monitoring hooks built-in.

It seems like you're trying to ask how to add drivers to ESXi on non-Dell/non-HP hardware. If that's the case...

Use supported hardware.

ESXi is bootstrapped by a small Busybox installation. There are only so many device drivers that can be shipped and supported effectively. Many systems that don't seem ESXi-compatible can be made to be compatible by just adding supported storage and network controllers. It's difficult to find server-class hardware that isn't supported by ESXi. If you're in a bind, just buy an Intel E1000 network card to complete your installation.