[isabelle-dev] Reclaiming disk space wasted by Oracle

[Makarius]

In the past few months, Oracle has been under constant attack and was 
emitting Java updates more frequently than usual.  This costs 800 MB disk 
space each time for our jdk Isabelle components.

People who do not work systematically with the Mercurial history (e.g. via 
hg bisect) can remove unused components manually. The usual invocation of 
"isabelle components -a" refetches missing components whenever they are 
needed again.

Since full download can take long especially for these buldy jdk packages, 
it is also possible to remove the *unpacked* component directory only, 
leaving the .tar.gz there.  This will be detected by "isabelle 
components", so it will unpack required components without another 
download.


 	Makarius