feat(java/driver/flight-sql): support flightsql:// URI scheme

[unikdahal]

What's Changed

Adds support for flightsql:// URIs to the Java Flight SQL driver, mirroring the Go driver's implementation (#4488).

• flightsql://<host>:<port> — secure TLS by default
• flightsql://<host>:<port>?transport=tls — explicit TLS
• flightsql://<host>:<port>?transport=tcp — plaintext gRPC
• flightsql:///<path/to/socket>?transport=unix — Unix domain socket

The transport value is matched case-insensitively; an unrecognized value is rejected with INVALID_ARGUMENT rather than silently falling back. Invalid
combinations (socket path with tcp/tls, host with unix, missing host/path) are rejected, matching the Go driver's validation and error messages. The
legacy grpc://, grpc+tcp://, grpc+tls://, and grpc+unix:// schemes are still accepted unchanged.

URIs with userinfo or a fragment are rejected explicitly, since Location would otherwise drop them silently. Parse failures that java.net.URI reports only
via Location's IllegalArgumentException (e.g. hostnames that fail strict authority parsing) are caught and surfaced as INVALID_ARGUMENT AdbcExceptions.

Testing

• New FlightSqlDriverUriTest: 18 unit tests covering translation of all transports, case-insensitivity, legacy scheme passthrough, a real connection over
  ?transport=tcp against an in-process Flight server, and rejection cases (unrecognized transport, invalid host/path combinations, userinfo, fragment, malformed
  percent-encoding, unparseable hosts).
• Two TLS tests added to TlsTest exercising flightsql:// default and explicit ?transport=tls against the TLS test server.

Closes #4516. Part of #4453.

[Copilot]

Pull request overview

Adds flightsql:// URI support to the Java Flight SQL ADBC driver (aligning with the Go driver), including transport selection via a transport query parameter and tighter validation/error surfacing. This updates URI parsing to translate flightsql:// into the legacy grpc+{tls,tcp,unix}:// forms that Arrow Flight Location understands, and expands test coverage for the new scheme.

Changes:

• Add FlightSqlDriver.parseLocation to translate/validate flightsql://... URIs (default TLS; transport=tcp|tls|unix case-insensitive; reject invalid combinations, userinfo, fragments, and malformed percent-encoding in transport).
• Add a new FlightSqlDriverUriTest suite covering translations, rejections, and a real TCP connection against an in-process server.
• Update TlsTest to cover flightsql:// default TLS and explicit ?transport=tls, and update FlightSqlDatabase#toString to include configured URI.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/FlightSqlDriver.java	Implements flightsql:// parsing/translation and validation into Flight Location.
java/driver/flight-sql/src/main/java/org/apache/arrow/adbc/driver/flightsql/FlightSqlDatabase.java	Enhances toString() to report configured URI alongside resolved target.
java/driver/flight-sql/src/test/java/org/apache/arrow/adbc/driver/flightsql/FlightSqlDriverUriTest.java	Adds unit/integration tests for new scheme behavior and validation.
java/driver/flight-sql/src/test/java/org/apache/arrow/adbc/driver/flightsql/TlsTest.java	Adds TLS coverage for flightsql:// default and explicit TLS transport.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (1)

java/driver/flight-sql/src/test/java/org/apache/arrow/adbc/driver/flightsql/TlsTest.java:191

• AdbcDatabase is created but never closed. Use try-with-resources so database (and any underlying resources) are always released, even if connect() throws.

  @Test
  public void testClientFlightSqlSchemeExplicitTlsTransport() throws Exception {
    params.put(AdbcDriver.PARAM_URI.getKey(), getFlightSqlUri("tls"));
    params.put(FlightSqlConnectionProperties.TLS_SKIP_VERIFY.getKey(), true);
    AdbcDatabase db =
        AdbcDriverManager.getInstance()
            .connect(FlightSqlDriverFactory.class.getCanonicalName(), allocator, params);
    try (AdbcConnection conn = db.connect()) {}
  }