Yeah, it is not going to compile everything. For most Java apps, which were built in a world where startup time was a known disadvantage of the JVM, they will probably be better off with a JITed VM anyway. This is more of a new capability, allowing JVM languages the ability to move into usecases where they have never shined before. Like CLI apps, for example. I would expect most usage of AOT compilation will be for new software, not existing software.

That being said, generics and factory patterns aren't a problem for graal at all. Reflection and dynamic class loading are the biggest offenders.