I can only agree with this. We rely heavily on both ASM and Javassist, and resource lookup/loading in general. While, as an agent, we can usually patch the bytecode to poke holes where needed, having a supported way to read resource bytes, similar to how getResourceAsStream works in jdk8, following the same logic as the JVM uses to locate classes, would be very welcome, so we wouldn't have to implement that kind of support for every single classloader implementation out there.
Currently, we have some code in place, that enables us to get the bytes for classes without knowing beforehand which module they are defined in, by basically mapping packages to modules. At the moment, this only works for named modules in the boot-layer though. /Michael Rasmussen