The-Compiler [1] filed a request to merge libgcj15-bin [2] into libgcj16-bin [3]:

libgcj16-bin (from GCC5) supersedes this package, and the only package which used it (pdftk-bin) now uses libgcj16.

Not sure if a merge or deletion is more appropriate.

[1] https://aur.archlinux.org/account/The-Compiler/ [2] https://aur.archlinux.org/pkgbase/libgcj15-bin/ [3] https://aur.archlinux.org/pkgbase/libgcj16-bin/