I was upgrading a package when I came across the following -$ sudo aptitude install openjdk-9-jre=9~b87-1 openjdk-9-jre-headless=9~b87-1 -yThe following packages will be upgraded:   openjdk-9-jre openjdk-9-jre-headless 2 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.Need to get 30.9 MB of archives. After unpacking 175 MB will be freed.Get: 1 http://httpredir.debian.org/debian/ experimental/main openjdk-9-jre amd64 9~b87-1 [39.4 kB]Get: 2 http://httpredir.debian.org/debian/ experimental/main openjdk-9-jre amd64 9~b87-1 [39.4 kB]                                                    Get: 3 http://httpredir.debian.org/debian/ experimental/main openjdk-9-jre-headless amd64 9~b87-1 [30.8 MB]                                           Fetched 30.9 MB in 21min 2s (24.4 kB/s)                                                                                                               Retrieving bug reports... DoneParsing Found/Fixed information... DoneReading changelogs... Doneapt-listchanges: Do you want to continue? [Y/n] yapt-listchanges: Mailing root: apt-listchanges: changelogs for think-debian(Reading database ... 375935 files and directories currently installed.)Preparing to unpack .../openjdk-9-jre_9~b87-1_amd64.deb ...Unpacking openjdk-9-jre:amd64 (9~b87-1) over (9~b80-2) ...Preparing to unpack .../openjdk-9-jre-headless_9~b87-1_amd64.deb ...Unpacking openjdk-9-jre-headless:amd64 (9~b87-1) over (9~b80-2) ...Processing triggers for gnome-menus (3.13.3-6) ...Processing triggers for mime-support (3.59) ...Processing triggers for desktop-file-utils (0.22-1) ...Setting up openjdk-9-jre-headless:amd64 (9~b87-1) ...update-binfmts: warning: /usr/share/binfmts/jar: no executable /usr/bin/jexec found, but continuing anyway as you requestSetting up openjdk-9-jre:amd64 (9~b87-1) ...Scanning processes...                                                                                                                                 Scanning linux images...                                                                                                                              Running kernel seems to be up-to-date.No services need to be restarted.No containers need to be restarted.Any ideas which /usr/bin/jexec is missing. 
the case of the missing /usr/bin/jexec
debian;java