The current LICENSE.txt in the codebase is Apache License Version 2.0. This is not suitable for a JSR Spec License.
There might be other OpenJDK related licenses (see the JSR 310 repository), but the spec itself has JCP requirements for a special license granted by the Spec Lead (Credit Suisse) Please ask PMO for help with that. The BSD-like license, JSR 310 currently contains is also not sufficient.
Apache License 2.0 is listed for RI and TCK, but following what most JSRs do here, there are likely separate projects or at least GitHub code-repositories for such artifacts. At the moment the project represents the Spec code. LICENSE.txt must be replaced or this file at least renamed (LICENSE_RI_TCK.txt or similar) for future reuse.