The class signature parsing code can fail with an unexpected error on invalid input:

jshell> ClassSignature.parseFrom("Ljava/lang/Object;Ljava/lang/Iterable<LFoo;>")
| Exception java.lang.StringIndexOutOfBoundsException: String index out of range: 44
| at StringLatin1.charAt (StringLatin1.java:48)
| at String.charAt (String.java:1517)
| at SignaturesImpl.referenceTypeSig (SignaturesImpl.java:137)
| at SignaturesImpl.parseClassSignature (SignaturesImpl.java:53)
| at ClassSignature.parseFrom (ClassSignature.java:84)
| at (#4:1)

I would expect that this method be specified to throw a specific exception on parse failure, and for the underlying code to then be consistent with that specification.

This was reported by a user using my downstream backport of this API to Java 17: https://github.com/dmlloyd/jdk-classfile-preview/issues/15 and also relates to JDK-8320360.