It's a nice start of the week to read this. As a Linux distro guy this makes me really happy as it's a first step in the right direction to fix some of the long standing problems for "source-first" developers. Java programs are full of references to libraries that have been cool and state of the art ~10 years ago but it's time to let them R.I.P.
Dropped support for old targets in javac will hopefully have the nice side effect to reducing the private patched jars many projects has in their scms. (Please stop including activation.jar with your app!)
Not to mention that it will help moving to newer JVMs - yes, I'm looking for the moment noone will ask me to compile my projects to target 1.5 as it would be just impossible. The answer would be awesome - javac don't support it anymore!
Sometimes I even wish to see something like "one plus FIVE back" for the JVM itself - aka Java 9 stop loading bytecode from pre-1.4 times. This would lead to huge cleanup in resources used by applications by making people look forward as now it's impossible to have a coherent support for even 2 application with the same set of libraries as each of them has stalled some dependency in the very distant past to the state it becomes impossible to collaborate. And NO, shipping private copies is not OK - search for the jakarta-httpclient CVEs which would not be fixed as it is EOLed and no further releases will happen(rightfully as it has been EOLed for years already!) but many applications expose their users by shipping a private copy most of the time not even knowing.
Even if this has been standing in my mind for quite some time I never expressed it in non-private conversation and reading that there is a hope made me start the week with some joy :).