feat(java/driver/flight-sql): add OAuth2 support

[lxyzxx]

Summary

This PR provides an initial implementation of OAuth2 authentication support for the Java Flight SQL ADBC driver.

It introduces a configurable OAuth2 mechanism that allows clients to acquire and attach access tokens when establishing Flight SQL connections.

Changes

• Add OAuth2-related connection options

  • token endpoint
  • client credentials
  • grant type (initial support focuses on client credentials flow)

• Introduce FlightSqlOAuthTokenProvider

  • Responsible for acquiring and refreshing access tokens
  • Encapsulates OAuth2 logic from the connection layer

• Integrate OAuth authentication into FlightSqlConnection

  • Automatically attaches Authorization: Bearer <token> header

• Add validation for conflicting authentication configurations

  • Prevent simultaneous usage of:
    • username/password
    • custom Authorization headers
    • OAuth2 configuration

• Add unit tests for OAuth2 authentication behavior

Future Work

• Consider whether OAuth2 support should be standardized across ADBC drivers
• Potentially introduce a common authentication abstraction at the ADBC layer

Closes #4277.

[lxyzxx]

Linked issue: #4277

[lidavidm]

FWIW, would using the existing Go Flight SQL driver via the JNI bridge work for you?

[lidavidm]

Is there a standard library/common third party library we can leverage for OAuth details?

[lxyzxx]

Thanks for the suggestions.

I’d prefer to keep this in the pure Java Flight SQL driver instead of relying on the Go driver through JNI, since JNI would introduce native dependencies and additional deployment complexity for Java users.

For the OAuth2 implementation, I agree that we should use an existing library rather than hand-roll the protocol details. I noticed that Arrow Java already uses Nimbus OAuth2 SDK, so I think Nimbus would be a good fit for Java ADBC as well. I’ll update the PR accordingly.

[xborder]

arrow-java implementation was based on the GO ADBC implementation and slightly changed to use Nimbus OAuth2 SDK. I think we could try to approximate ADBC and JDBC implementations, it might be possible to use arrow-java implementation since it seems ADBC has arrow-java as a dependency

[lxyzxx]

That makes sense. Since ADBC currently depends on Arrow Java 18.3.0 and the Arrow Java OAuth classes are not available in that version yet, directly reusing the JDBC implementation would require bumping the Arrow Java dependency.

Would you prefer that I refactor the ADBC implementation in this PR to more closely mirror the Arrow Java JDBC OAuth structure, or should we wait until ADBC updates to an Arrow Java version that includes those OAuth classes and then reuse the implementation ?

[xborder]

I think it is ok to bump arrow-java version. 19.0.0 already got released. That way, refactoring the implementation to make it closer to arrow-java would be simpler