Elfs are standard unix binary executable files (like windows .exe). Every program is distributed like independent file. It's possible to run elf files on Sony Ericsson phones.
Their benefits of Elf files over Java(apps and games) include:
The program is directly using the processor and memory resources, without any virtual machine limitations. In other words - ELF programs are faster programs.
If you want extreme detail then check this:
I'l be posting elfpacks for some phones here. Elfpacks allow your phone to run elfs!!
Those phones will be : K750/W700/W800/W810/Z550/W550/K810
Get the K750 R1CA021 elfpack from here
Get the W700 R1CA021 elfpack from here
Get the W800 R1DB001 elfpack from here
Get the W810 R4EA031 elfpack from here
Get the Z550 R6CA009 elfpack from here
Get the W550 R4CB020 elfpack from here
Get the W610 R6BC002 elfpack from here
Get the W580 R8BA024 elfpack from here
Get the W660 R8BB001 elfpack from here
Get the W660 R6AD001 elfpack from here
Get the W830 R1KG001 elfpack from here
Get the W850 R1KG001 elfpack from here
Get the K800 R8BF003 elfpack from here
Get the K810 R8BA024 elfpack from here
If a few elfs don't work then try using these DYN_CONST.bin files, they're the newest:
Also, update your library patches from here:
Some elfs wont work unless u have the latest versions of both the DYN_CONST file or the latest library.