I'm trying to use this with the emulator and without providing valid (or any) gcloud default application credentials but having issues.

I am passing BIGTABLE_EMULATOR_HOST

First the lib complains of not having a project ID.
[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project seeder: An exception occured while executing the Java class. null: InvocationTargetException: Could not find an appropriate constructor for com.google.cloud.bigtable.hbase1_2.BigtableConnection: Project ID must be supplied via google.bigtable.project.id -> [Help 1]

Is this relevant for the emulator? Let's plow forwards and give it that info.

Now I can see it outputs a line confirming it understood the BIGTABLE_EMULATOR_HOST.
BigtableOptions:75 - Connecting to the Bigtable emulator at bigtable:8820

but then...

[ERROR] Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.2.1:java (default-cli) on project seeder: An exception occured while executing the Java class. null: InvocationTargetException: Could not find an appropriate constructor for com.google.cloud.bigtable.hbase1_2.BigtableConnection: The Application Default Credentials are not available. They are available if running in Google Compute Engine. Otherwise, the environment variable GOOGLE_APPLICATION_CREDENTIALS must be defined pointing to a file defining the credentials. See https://developers.google.com/accounts/docs/application-default-credentials for more information. -> [Help 1]

We need application_default_credentials. Why?

If I provide real credentials things work, but if I fake them, it fails to auth. Is there some way to configure things so we deal with the emulator only and are not depending on this file and not phoning home to google cloud? It seems like once it sees BIGTABLE_EMULATOR_HOST it should understand not to do any auth stuff with gcloud.

Thanks