DOM Level 3+Bootstrapping

Hi All,
Can any one helps me to understand bootstrapping DOM Level 3 concept,
I am implementing in c++,i have following Questions
1)Is registry is persistent?or shall i force the application user to register everytime using AddSource()..
2)Suppose i have only one implementation like MyDOM how do i register this MyDOM,
how do i make this MyDOM as object of DOMImplementationSource,
3)If i have only one implementation,i think bootstrapping is not useful???

Please help to understand bootstrapping ,

Thanking u in advance,
Regards,
Pavithran