JDK-8294961 changed to use classfile API for reflection proxy-generation, which is the cause of a number of startup and footprint regressions in a few of our internal benchmarks.

There are a few things that stand out: the cost of generating the ProxyGenerator.TEMPLATE used for proxies, and that the code touches a number of bootstrapped switch expressions. There are a number of minor things, some of which have been addressed since this regression manifested in 23-b13.

One thing to examine is how much of the relative startup overhead can be avoided by using a plain code generator instead of creating a reusable template up front.