[Java IO] Add ArrowFlight IO connector

Add a new IO connector for Apache Arrow Flight, enabling high-performance
data transfer over gRPC using the Arrow columnar format.

Includes read (BoundedSource) and write (DoFn with doPut) support with
endpoint-level split parallelism and bearer token authentication.

Fixes #20116

Author: bvolpato

CHANGES.md

@@ -65,6 +65,7 @@
 ## I/Os
 
 * Support for X source added (Java/Python) ([#X](https://github.com/apache/beam/issues/X)).
+* Add ArrowFlight IO (Java) ([#20116](https://github.com/apache/beam/issues/20116)).
 * DebeziumIO (Java): added `OffsetRetainer` interface and `FileSystemOffsetRetainer` implementation to persist and restore CDC offsets across pipeline restarts, and exposed `withStartOffset` / `withOffsetRetainer` on `DebeziumIO.Read` and the cross-language `ReadBuilder` ([#28248](https://github.com/apache/beam/issues/28248)).
 
 ## New Features / Improvements

buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy

@@ -925,6 +925,8 @@ class BeamModulePlugin implements Plugin<Project> {
         arrow_vector                                : "org.apache.arrow:arrow-vector:$arrow_version",
         arrow_memory_core                           : "org.apache.arrow:arrow-memory-core:$arrow_version",
         arrow_memory_netty                          : "org.apache.arrow:arrow-memory-netty:$arrow_version",
+        arrow_flight_core                           : "org.apache.arrow:flight-core:$arrow_version",
+        arrow_flight_sql                            : "org.apache.arrow:flight-sql:$arrow_version",
       ],
       groovy: [
         groovy_all: "org.codehaus.groovy:groovy-all:2.4.13",

sdks/java/io/arrow-flight/build.gradle

@@ -0,0 +1,39 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * License); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an AS IS BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+plugins { id 'org.apache.beam.module' }
+applyJavaNature(automaticModuleName: 'org.apache.beam.sdk.io.arrowflight')
+
+description = "Apache Beam :: SDKs :: Java :: IO :: Arrow Flight"
+ext.summary = "IO to read and write data using Apache Arrow Flight RPC."
+
+dependencies {
+  implementation project(path: ":sdks:java:core", configuration: "shadow")
+  implementation project(path: ":sdks:java:extensions:arrow")
+  implementation library.java.joda_time
+  implementation library.java.slf4j_api
+  implementation library.java.vendored_guava_32_1_2_jre
+  implementation(library.java.arrow_flight_core)
+  implementation(library.java.arrow_memory_core)
+  implementation(library.java.arrow_vector)
+  testImplementation library.java.hamcrest
+  testImplementation library.java.junit
+  testImplementation(library.java.arrow_memory_netty)
+  testRuntimeOnly library.java.slf4j_simple
+  testRuntimeOnly project(path: ":runners:direct-java", configuration: "shadow")
+}