Since today, the NetBeans latest build  is available bundled with GlassFish 4.0.1 (build 09).
GlassFish 4.0.1 includes newer versions of JSF, CDI and more. And, the most important fact: You can launch it using Java 8.
If you search the net, you might find blogs reporting GlassFish 4.0 successfully running on Java 8. I tried the same. Although most application ran, sometimes GlassFish showed a strange behavior, e.g. objects might not be initialized as expected. With GlassFish 4.0.1 (since build 06), I haven’t faced such problems.