ECB is a file/code browser for Emacs. It can be used to browse any type of file and supports parsing of Java, C, C++, Elisp and some other code like perl, TeX, LaTeX. All browsing windows are within one frame and they are deletion-protected (eg by C-x 1)
Kawa is a full Scheme implementation. It implements almost all of R5RS (for exceptions see Restrictions), plus some extensions.