Problem with client secret

[l-g]

% java -jar ./target/mail-importer-0.0.0-SNAPSHOT-jar-with-dependencies.jar --mailbox /tmp/export/forum.mbox/
Exception in thread "main" com.google.inject.ProvisionException: Unable to provision, see the following errors:

1) Error in custom provider, java.lang.IllegalArgumentException: 
  while locating to.lean.tools.gmail.importer.gmail.Authorizer
  at to.lean.tools.gmail.importer.gmail.GmailServiceModule.configure(GmailServiceModule.java:43)
  while locating com.google.api.client.auth.oauth2.Credential
    for parameter 1 at to.lean.tools.gmail.importer.gmail.GmailService.<init>(GmailService.java:46)
  at to.lean.tools.gmail.importer.gmail.GmailServiceModule.configure(GmailServiceModule.java:42)
  while locating to.lean.tools.gmail.importer.gmail.GmailService
    for parameter 0 at to.lean.tools.gmail.importer.gmail.Mailbox.<init>(Mailbox.java:73)
  while locating to.lean.tools.gmail.importer.gmail.Mailbox
    for parameter 0 at to.lean.tools.gmail.importer.gmail.GmailSyncer.<init>(GmailSyncer.java:39)
  while locating to.lean.tools.gmail.importer.gmail.GmailSyncer
    for parameter 2 at to.lean.tools.gmail.importer.Importer.<init>(Importer.java:90)
  while locating to.lean.tools.gmail.importer.Importer

1 error
	at com.google.inject.internal.InjectorImpl$2.get(InjectorImpl.java:1025)
	at com.google.inject.internal.InjectorImpl.getInstance(InjectorImpl.java:1051)
	at to.lean.tools.gmail.importer.Importer.main(Importer.java:81)
Caused by: java.lang.IllegalArgumentException: 
	at com.google.api.client.json.JsonParser.parseValue(JsonParser.java:880)
	at com.google.api.client.json.JsonParser.parse(JsonParser.java:381)
	at com.google.api.client.json.JsonParser.parse(JsonParser.java:335)
	at com.google.api.client.json.JsonParser.parseAndClose(JsonParser.java:165)
	at com.google.api.client.json.JsonParser.parseAndClose(JsonParser.java:147)
	at com.google.api.client.json.JsonFactory.fromReader(JsonFactory.java:236)
	at com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets.load(GoogleClientSecrets.java:192)
	at to.lean.tools.gmail.importer.gmail.Authorizer.loadGoogleClientSecrets(Authorizer.java:131)
	at to.lean.tools.gmail.importer.gmail.Authorizer.get(Authorizer.java:66)
	at to.lean.tools.gmail.importer.gmail.Authorizer.get(Authorizer.java:49)

Caused by: java.lang.IllegalArgumentException: expected numeric type but got class com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets
	at com.google.api.client.json.JsonParser.parseValue(JsonParser.java:843)

I have put my client secret in a file called client_secret.json, but the instructions are a bit unclear - should the filename actually be the key?

The result should be a JSON file named something like:

client_secret_729820383-898athoe9t33ntohuoc.apps.googleusercontent.com.json

That is, is client_secret.json the name of the directory rather than the file?

I guess the prefix client_secret should be replaced with some random characters?

My client secret looks like this:

13 digits dash 32 mixed digits and letters followed by .apps.googleusercontent.com

but that one is labelled "client ID" in the Google Console while the "client secret" is a mix of 24 digits and characters with no suffix (like in your example and my client ID).

Can you clarify?

Thank you