SIGSEV on env->FindClass

[Erhannis]

I've compiled the heapTagger example, both the c and the java (via make and mvn clean package), but when I run it with
java -agentlib:taggingExample -cp .:HeapTaggingExample-0.0.1-SNAPSHOT.jar net.jonbell.examples.jvmti.tagging.Main
I get a SIGSEV. (Original dump attached. hs_err_pid11542.log) By adding a bunch of logging, I pinpointed the crash in env->FindClass(), in cbVMStart. Any idea why it would be crashing there? I didn't change any code before the crash happened. I'm on commit c00c41d. /proc/version reads

Linux version 4.9.0-5-amd64 (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170516 (Debian 6.3.0-18) ) #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04)

Java version output:

java version "1.8.0_191"
Java(TM) SE Runtime Environment (build 1.8.0_191-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.191-b12, mixed mode)