In two places in the package documentation for the java.lang.module package, the phrase "at the discretion of the host system" occurs.
I feel like it is trying to tell me something important, and I understand the English, but I fail to see what that important something might be.
Here is one of two possible examples drawn from the documentation (with my emphasis):
Recursive enumeration takes a set of module names, looks up each of their module declarations, and for each module declaration, recursively enumerates:
- the module names given by the 'requires' directives with the 'transitive' modifier, and
- at the discretion of the host system, the module names given by the 'requires' directives without the 'transitive' modifier.
If my module-info.java file has, simply, requires foo; (i.e. not requires transitive foo;), and foo exists in some way, is it the case that the "host system" can simply pretend that foo does not participate in the resolved module graph? What could be a reason for calling this out explicitly?