Ksplice was around long before Oracle picked it up. I used it for a while, but I had a few problems with it. I was using it to patch-in instrumented kernels for debugging.
I went back to using kexec-tools for a while, but realized the best way to be sure that you have a fresh kernel is to reboot.
Also, dynamic kernel patching won’t work with Secure Boot technology. The workaround for now is to disable secure boot in the ROM-based Setup (UEFI). Don’t know if there are plans to make it work with secure boot.
This goes way, way back. In the 70s mainframes did this all the time. I worked on sherry and univac mainframes, and I often patched the Dispatcher algorithms on the fly.
But, since most of today’s kids have never worked on mainframes, this seemed a novelty to them.
Same for the concept of virtual machines. These are not new concepts, but implemented decades previous.
Nothing new under the sun (except to those who were not alive back then).