I am a programmer in another field now, but I would like to get into software development in financial institution in future. I will try to finish SCWCD soon, so I would like to know how those companies apple SCWCD related technology.
Not sure what exactly you mean by "apply" - servlets and JSP are used wherever people write web apps in Java. More often than not, these days servlets are not used directly, but as the underlying technology in some web framework or other (like Struts, Stripes, Seam, etc.), so that's what you'll see in job ads.
Note that not all companies that use Java extensively also use it for the web layer - they might use it for the business layer, but write the web layer in some other technology (like PHP).