Class java.lang.reflect.ProxyGenerator generates proxy class files without stackmaps, requiring these classes to be class file version 49, so they can be verified by the old verifier.

This is a potential problem if a class file version dependent entity needs to be added to a proxy class.  One example of this is project Valhalla's ValueType attribute for class file versions >= 55.  According to the JVM Spec, this attribute should be ignored in old class files, preventing the JVM from recognizing value type references in proxy classes.

ProxyGenerator should be re-written (using asm?) to generate classes whose class file version is the JDK's latest supported version.