write to output in the doAfterBody

[chris noe]

Hello,

I'm studying for the SCWCD exam and i'm a bit confused about the following :
Can someone tell me the difference between :

JspWriter wrt = getBodyContent.getEnclosingWriter();
JspWriter wrt = getPreviousOut();
JspWriter wrt = getPageContext.getOut();

in the doAfterBodyMethod of a class extending the BodyTagSupport.
Doesn't all the 'wrt' write to the same output ?

Tnx,
Chris.