i notice the applcation that was build on JSF 2 & Richfaces 4 do not required to add <f:view> tag in the page am i right or wrong ?
you are correct.
Before JSF 2.0, all JSF pages had to be enclosed in f:view tags.
Nowadays, this is no longer necessary. However, the f:view tag is still occasionally
useful; for example, for setting the locale.