Illegal access error when deleting Google Pub Sub subscription upon JVM shutdown

Question

I'm trying to delete a Google Pub Sub subscription in a JVM shutdown hook, but I'm encountering an illegal access error with the Google Pub Sub subscription admin client when the shutdown hook runs. I've tried using both sys.addShutdownHook as well as Runtime.getRuntime().addShutdownHook, but I get the same error either way.

val deleteInstanceCacheSubscriptionThread = new Thread {
  override def run: Unit = {
     cacheUpdateService. deleteInstanceCacheUpdateSubscription()
  }
}
sys.addShutdownHook(deleteInstanceCacheSubscriptionThread.run)
// Runtime.getRuntime().addShutdownHook(deleteInstanceCacheSubscriptionThread)

This is the stack trace:

Exception in thread "shutdownHook1" java.lang.IllegalStateException: Illegal access: this web application instance has been stopped already. Could not load [META-INF/services/com.google.auth.http.HttpTransportFactory]. The following stack trace is thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access.
    at org.apache.catalina.loader.WebappClassLoaderBase.checkStateForResourceLoading(WebappClassLoaderBase.java:1385)
    at org.apache.catalina.loader.WebappClassLoaderBase.findResources(WebappClassLoaderBase.java:985)
    at org.apache.catalina.loader.WebappClassLoaderBase.getResources(WebappClassLoaderBase.java:1086)
    at java.util.ServiceLoader$LazyIterator.hasNextService(ServiceLoader.java:348)
    at java.util.ServiceLoader$LazyIterator.hasNext(ServiceLoader.java:393)
    at java.util.ServiceLoader$1.hasNext(ServiceLoader.java:474)
    at com.google.common.collect.Iterators.getNext(Iterators.java:845)
    at com.google.common.collect.Iterables.getFirst(Iterables.java:779)
    at com.google.auth.oauth2.OAuth2Credentials.getFromServiceLoader(OAuth2Credentials.java:318)
    at com.google.auth.oauth2.ServiceAccountCredentials.<init>(ServiceAccountCredentials.java:145)
    at com.google.auth.oauth2.ServiceAccountCredentials.createScoped(ServiceAccountCredentials.java:505)
    at com.google.api.gax.core.GoogleCredentialsProvider.getCredentials(GoogleCredentialsProvider.java:92)
    at com.google.api.gax.rpc.ClientContext.create(ClientContext.java:142)
    at com.google.cloud.pubsub.v1.stub.GrpcSubscriberStub.create(GrpcSubscriberStub.java:263)
    at com.google.cloud.pubsub.v1.stub.SubscriberStubSettings.createStub(SubscriberStubSettings.java:242)
    at com.google.cloud.pubsub.v1.SubscriptionAdminClient.<init>(SubscriptionAdminClient.java:178)
    at com.google.cloud.pubsub.v1.SubscriptionAdminClient.create(SubscriptionAdminClient.java:159)
    at com.google.cloud.pubsub.v1.SubscriptionAdminClient.create(SubscriptionAdminClient.java:150)
    at com.company.pubsub.services.GooglePubSubService.$anonfun$deleteSubscription$2(GooglePubSubService.scala:384)
    at com.company.utils.TryWithResources$.withResources(TryWithResources.scala:21)
    at com.company.pubsub.services.GooglePubSubService.$anonfun$deleteSubscription$1(GooglePubSubService.scala:384)
    at com.company.scalalogging.Logging.time(Logging.scala:43)
    at com.company.scalalogging.Logging.time$(Logging.scala:35)
    at com.company.pubsub.services.GooglePubSubService.time(GooglePubSubService.scala:30)
    at com.company.pubsub.services.GooglePubSubService.deleteSubscription(GooglePubSubService.scala:382)
    at com.company.cache.services.CacheUpdateService.deleteInstanceCacheUpdateSubscription(CacheUpdateService.scala:109)
    at com.company.cache.services.CacheUpdateHandlerService$$anon$1.run(CacheUpdateHandlerService.scala:132)
    at com.company.cache.services.CacheUpdateHandlerService$.$anonfun$addSubscriptionShutdownHook$1(CacheUpdateHandlerService.scala:135)
    at scala.sys.ShutdownHookThread$$anon$1.run(ShutdownHookThread.scala:37)

It seems like by the time the shutdown hook runs the Pub Sub library has already shut down, so we can't access the subscription admin client anymore. But, I was wondering if there was anyway to delete the subscription before this happens.