small changes, long build time

Alan Bateman Alan.Bateman at
Sat Apr 30 06:18:28 UTC 2016

On 30/04/2016 00:46, Pete Brunet wrote:
> Even small edits to code in the jdk source tree result in very long time
> build times now that jigsaw is merged in.  Is anyone working on trying
> to improve that?  Is there a workaround?
When you touch code in a module then you can use "make <module>" to just 
rebuild that module. If you use "make" then it will rebuild that module 
and all other modules that directly or transitively depend on it. There 
are some tricks with sjavac but that is essentially it.

So which module are you changing? Is this Windows? Are you re-building 
images each time?

If you are re-building images every time then you'll see it creates the 
jmods (packaged modules too). It is a bit expensive at moment, partly 
because each package module generates hashes of the module artifact of 
each dependency. This has been changed in an upcoming refresh so that 
the hashes are generated and recorded once, this in turn allows for more 
concurrency when generating the packaged modules. This may help you, but 
hard to say.


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