chore: Check java9+ classes in paradox.

.github/workflows/generate-paradox-check.yml

@@ -0,0 +1,48 @@
+# 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.
+
+name: Generate paradox check
+
+on:
+  pull_request:
+
+permissions:
+  contents: read
+
+jobs:
+  generate-doc-check:
+    name: Generate paradox check
+    runs-on: ubuntu-20.04
+    if: github.repository == 'apache/incubator-pekko'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          fetch-tags: true
+
+      - name: Setup Java 11
+        uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: 11
+
+      - name: Cache Coursier cache
+        uses: coursier/[email protected]
+
+      - name: Compile paradox documents
+        run: sbt ";clean ;Test / compile ;TestJdk9 / compile ;docs/paradox"

docs/src/test/java-jdk9-only/jdocs/stream/operators/source/AsSubscriber.java

@@ -20,7 +20,6 @@
 import org.apache.pekko.NotUsed;
 import org.apache.pekko.stream.javadsl.Source;
 import org.apache.pekko.stream.javadsl.JavaFlowSupport;
-
 //#imports
 public interface AsSubscriber {
     // We are 'faking' the JavaFlowSupport API here so we can include the signature as a snippet in the API,

docs/src/test/scala/docs/stream/operators/sink/AsPublisher.scala

@@ -13,10 +13,11 @@
 
 package docs.stream.operators.sink
 
-import scala.concurrent.{ ExecutionContextExecutor, Future }
 import org.apache.pekko.actor.ActorSystem
 import org.apache.pekko.stream.scaladsl.{ Sink, Source }
 
+import scala.concurrent.ExecutionContextExecutor
+
 object AsPublisher {
   implicit val system: ActorSystem = ???
   implicit val ec: ExecutionContextExecutor = system.dispatcher