javax.script.ScriptEngineManager.init(ClassLoader) does its own implementation of searching for engines in META-INF/services/javax.script.ScriptEngineFactory. But this is silly because sun.misc.Service.providers(Class,ClassLoader) already accomplishes the same thing in a standardized way.

Furthermore, the ScriptEngineManager version incorrectly uses the platform default encoding to read these files, whereas UTF-8 is mandated. It may have other minor bugs, I am not sure.