The following code (suggested in documentation) results in an error:

Iterator<Blob> it = storage.list(COVER).iterateAll();
while (it.hasNext()) {

    Blob blob = it.next();
    storage.updateAcl(blob.blobId(), Acl.of(User.ofAllUsers(), Role.READER));
    // blob.updateAcl(Acl.of(User.ofAllUsers(), Role.READER));  - results in the same error
}

The error message (not very useful):

Exception in thread "main" com.google.cloud.storage.StorageException: Not Found
at com.google.cloud.storage.spi.DefaultStorageRpc.translate(DefaultStorageRpc.java:198)
at com.google.cloud.storage.spi.DefaultStorageRpc.patchAcl(DefaultStorageRpc.java:818)
at com.google.cloud.storage.StorageImpl$33.call(StorageImpl.java:827)
at com.google.cloud.storage.StorageImpl$33.call(StorageImpl.java:824)
at com.google.cloud.RetryHelper.doRetry(RetryHelper.java:179)
at com.google.cloud.RetryHelper.runWithRetries(RetryHelper.java:244)
at com.google.cloud.storage.StorageImpl.updateAcl(StorageImpl.java:824)
at com.rebelation.ingest.server.VerifyCoverFiles.main(VerifyCoverFiles.java:52)
Caused by: com.google.api.client.googleapis.json.GoogleJsonResponseException: 404 Not Found
{
"code" : 404,
"errors" : [ {
"domain" : "global",
"message" : "Not Found",
"reason" : "notFound"
} ],
"message" : "Not Found"
}
at com.google.api.client.googleapis.json.GoogleJsonResponseException.from(GoogleJsonResponseException.java:146)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:113)
at com.google.api.client.googleapis.services.json.AbstractGoogleJsonClientRequest.newExceptionOnError(AbstractGoogleJsonClientRequest.java:40)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest$1.interceptResponse(AbstractGoogleClientRequest.java:321)
at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1056)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:419)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.executeUnparsed(AbstractGoogleClientRequest.java:352)
at com.google.api.client.googleapis.services.AbstractGoogleClientRequest.execute(AbstractGoogleClientRequest.java:469)
at com.google.cloud.storage.spi.DefaultStorageRpc.patchAcl(DefaultStorageRpc.java:813)
... 6 more