The type java.util.concurrent.Flow$Publisher cannot be resolved

导入最新的spring源码时（2017.11.24），

Description ResourcePath LocationType

The type java.util.concurrent.Flow$Publisher cannot be resolved. It is indirectly referenced from required .class filesReactiveAdapterRegistry.java /spring-core/src/main/java/org/springframework/coreline 1 Java Problem

Description ResourcePath LocationType
The project was not built since its build path is incomplete. Cannot find the class file for java.util.concurrent.Flow$Publisher. Fix the build path then try building this projectspring-core UnknownJava Problem

应该是最新的源码用到了Java9 的新特性了吧，换成JDK9错误消失。