Need help implementing Java modules

Alex Buckley alex.buckley at
Tue May 9 22:39:14 UTC 2017

On 5/9/2017 3:04 PM, Ralph Goers wrote:
> Pardon me for being dense, but my reading said that Java modules
> disallowed runtime cycles as well as compile time. Once LoggerFinder
> binds with the module that provides that service does that not create
> a runtime dependency?  I don’t recall seeing anything describing what
> the behavior of that is.

The module system disallows cycles in the 'requires' directives of 
module declarations. The module system allows cycles in the "reads" 
relation of run-time modules.

When java.base 'uses LoggerFinder;' and invokes ServiceLoader to find 
providers, there is indeed a "reads" cycle created between the provider 
module and java.base. ServiceLoader is not special in creating this 
cycle -- you can create them yourself with the two addReads methods in 
the API, and all automatic modules have cyclic readability. But there is 
no 'requires' cycle.


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