About SUSELinux memory specification

Hi, I have a question about SUSELinux memory specification.

Basically, is it correct that Linux allocates swap space for processing?
If not
If physical memory is insufficient, does it use virtual memory in the swap area?
Also, if a process exceeds the capacity of physical memory, will the system immediately go down?
Does the use of virtual memory prevent the system from going down?

For example
I would like to know if it is possible to run an application that uses 5GB at a time on a server that is loaded with 3GB.
Does zLinux behave in such a way that it swaps the mostly unused memory portion of a 3GB app to free up memory to run a 2GB app?
The version is SUSE11.