Summary

Layer.defineModulesXXX with a Configuration containing java.base throws undocumented exception

Problem

The module "java.base" is the core module in Java SE. It can only exist in the boot Layer.

The current API to create module Layer (java.lang.reflect.Layer) doesn't currently specify this restriction and so trips up JCK tests that attempt to create custom module Layers with a module named "java.base".

Solution

Clarify the spec to make so that it clear that java.base is only allowed in the boot Layer.

Update the Layer::defineModulesXXXX methods to define the exception thrown when attempting to create a custom layer containing "java.base".

Specification

See attached specdiffs.