diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSinkSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSinkSpec.scala
index 69404da9d7..4fb3c513b2 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSinkSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSinkSpec.scala
@@ -176,5 +176,15 @@ class QueueSinkSpec extends StreamSpec {
         Source.single(()).runWith(Sink.queue().withAttributes(inputBuffer(0, 0)))
       }
     }
+
+    "materialize to a queue which is seamlessly translatable between scala and java DSL" in assertAllStagesStopped {
+      val expected = List(Some(1), Some(2), Some(3), None)
+      val javadslQueue = Source(expected.flatten).runWith(Sink.queue()).asJava
+      val scaladslQueue = akka.stream.javadsl.SinkQueueWithCancel.asScala(javadslQueue)
+      expected.foreach { v ⇒
+        scaladslQueue.pull().pipeTo(testActor)
+        expectMsg(v)
+      }
+    }
   }
 }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSourceSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSourceSpec.scala
index 1da9a4719c..41c009c7e6 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSourceSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/QueueSourceSpec.scala
@@ -356,6 +356,24 @@ class QueueSourceSpec extends StreamSpec {
       }
     }
 
+    "materialize to a queue which is seamlessly translatable between scala and java DSL" in {
+      val s = TestSubscriber.manualProbe[Int]()
+
+      val javadslQueue = Source.queue(10, OverflowStrategy.fail).to(Sink.fromSubscriber(s)).run().asJava
+      val scaladslQueue = akka.stream.javadsl.SourceQueueWithComplete.asScala(javadslQueue)
+      val sub = s.expectSubscription()
+
+      sub.request(1)
+      assertSuccess(scaladslQueue.offer(42))
+      s.expectNext(42)
+
+      scaladslQueue.watchCompletion().pipeTo(testActor)
+      expectNoMessage(pause)
+
+      sub.cancel()
+      expectMsg(Done)
+    }
+
   }
 
 }
diff --git a/akka-stream/src/main/mima-filters/2.5.22.backwards.excludes b/akka-stream/src/main/mima-filters/2.5.22.backwards.excludes
index ddb5a46860..edade4e1ec 100644
--- a/akka-stream/src/main/mima-filters/2.5.22.backwards.excludes
+++ b/akka-stream/src/main/mima-filters/2.5.22.backwards.excludes
@@ -11,3 +11,7 @@ ProblemFilters.exclude[IncompatibleResultTypeProblem]("akka.stream.impl.io.Conne
 ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.stream.impl.io.ConnectionSourceStage.this")
 ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.stream.impl.io.OutgoingConnectionStage.this")
 ProblemFilters.exclude[DirectMissingMethodProblem]("akka.stream.scaladsl.MergeHub#MergedSourceLogic.this")
+
+# #25045 adding Java/Scala interop to SourceQueue and SinkQueue
+ProblemFilters.exclude[MissingClassProblem]("akka.stream.impl.SinkQueueAdapter")
+ProblemFilters.exclude[MissingClassProblem]("akka.stream.impl.SourceQueueAdapter")
diff --git a/akka-stream/src/main/scala/akka/stream/impl/QueueSource.scala b/akka-stream/src/main/scala/akka/stream/impl/QueueSource.scala
index 1990ee4a18..0902270639 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/QueueSource.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/QueueSource.scala
@@ -4,15 +4,12 @@
 
 package akka.stream.impl
 
-import java.util.concurrent.CompletionStage
-
 import akka.Done
 import akka.annotation.InternalApi
 import akka.stream.OverflowStrategies._
 import akka.stream._
 import akka.stream.stage._
 import akka.stream.scaladsl.SourceQueueWithComplete
-import scala.compat.java8.FutureConverters._
 import scala.concurrent.{ Future, Promise }
 
 /**
@@ -214,14 +211,3 @@ import scala.concurrent.{ Future, Promise }
     (stageLogic, stageLogic)
   }
 }
-
-/**
- * INTERNAL API
- */
-@InternalApi private[akka] final class SourceQueueAdapter[T](delegate: SourceQueueWithComplete[T])
-    extends akka.stream.javadsl.SourceQueueWithComplete[T] {
-  def offer(elem: T): CompletionStage[QueueOfferResult] = delegate.offer(elem).toJava
-  def watchCompletion(): CompletionStage[Done] = delegate.watchCompletion().toJava
-  def complete(): Unit = delegate.complete()
-  def fail(ex: Throwable): Unit = delegate.fail(ex)
-}
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala b/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala
index 70f2b1b6a9..f516390331 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Sinks.scala
@@ -4,32 +4,36 @@
 
 package akka.stream.impl
 
-import java.util.Optional
-import java.util.concurrent.CompletionStage
+import scala.annotation.unchecked.uncheckedVariance
+import scala.collection.immutable
+import scala.collection.mutable
+import scala.concurrent.Future
+import scala.concurrent.Promise
+import scala.util.Failure
+import scala.util.Success
+import scala.util.Try
+import scala.util.control.NonFatal
 
 import akka.NotUsed
-import akka.actor.{ ActorRef, Props }
-import akka.annotation.{ DoNotInherit, InternalApi }
+import akka.actor.ActorRef
+import akka.actor.Props
+import akka.annotation.DoNotInherit
+import akka.annotation.InternalApi
 import akka.dispatch.ExecutionContexts
 import akka.event.Logging
 import akka.stream.Attributes.InputBuffer
 import akka.stream._
-import akka.stream.impl.QueueSink.{ Output, Pull }
+import akka.stream.impl.QueueSink.Output
+import akka.stream.impl.QueueSink.Pull
 import akka.stream.impl.Stages.DefaultAttributes
 import akka.stream.impl.StreamLayout.AtomicModule
-import akka.stream.scaladsl.{ Sink, SinkQueueWithCancel, Source }
+import akka.stream.scaladsl.Sink
+import akka.stream.scaladsl.SinkQueueWithCancel
+import akka.stream.scaladsl.Source
 import akka.stream.stage._
-import org.reactivestreams.{ Publisher, Subscriber }
-
-import scala.annotation.unchecked.uncheckedVariance
-import scala.collection.{ immutable, mutable }
-import scala.compat.java8.FutureConverters._
-import scala.compat.java8.OptionConverters._
-import scala.concurrent.{ Future, Promise }
-import scala.util.control.NonFatal
-import scala.util.{ Failure, Success, Try }
-import scala.collection.immutable
 import akka.util.ccompat._
+import org.reactivestreams.Publisher
+import org.reactivestreams.Subscriber
 
 /**
  * INTERNAL API
@@ -441,17 +445,6 @@ import akka.util.ccompat._
   }
 }
 
-/**
- * INTERNAL API
- */
-@InternalApi private[akka] final class SinkQueueAdapter[T](delegate: SinkQueueWithCancel[T])
-    extends akka.stream.javadsl.SinkQueueWithCancel[T] {
-  import akka.dispatch.ExecutionContexts.{ sameThreadExecutionContext => same }
-  def pull(): CompletionStage[Optional[T]] = delegate.pull().map(_.asJava)(same).toJava
-  def cancel(): Unit = delegate.cancel()
-
-}
-
 /**
  * INTERNAL API
  *
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Queue.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Queue.scala
index d00da3cc4b..e534a71a1c 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Queue.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Queue.scala
@@ -10,29 +10,33 @@ import java.util.concurrent.CompletionStage
 import akka.Done
 import akka.stream.QueueOfferResult
 
+import scala.compat.java8.FutureConverters._
+import scala.compat.java8.OptionConverters._
+import scala.concurrent.Future
+
 /**
- * This trait allows to have the queue as a data source for some stream.
+ * This trait allows to have a queue as a data source for some stream.
  */
 trait SourceQueue[T] {
 
   /**
-   * Method offers next element to a stream and returns future that:
-   * - completes with `Enqueued` if element is consumed by a stream
-   * - completes with `Dropped` when stream dropped offered element
-   * - completes with `QueueClosed` when stream is completed during future is active
-   * - completes with `Failure(f)` when failure to enqueue element from upstream
-   * - fails when stream is completed
+   * Offers an element to a stream and returns a [[CompletionStage]] that:
+   * - completes with `Enqueued` if the element is consumed by a stream
+   * - completes with `Dropped` when the stream dropped the offered element
+   * - completes with `QueueClosed` when the stream is completed whilst the [[CompletionStage]] is active
+   * - completes with `Failure(f)` in case of failure to enqueue element from upstream
+   * - fails when stream is already completed
    *
    * Additionally when using the backpressure overflowStrategy:
-   * - If the buffer is full the Future won't be completed until there is space in the buffer
-   * - Calling offer before the Future is completed in this case will return a failed Future
+   * - If the buffer is full the [[CompletionStage]] won't be completed until there is space in the buffer
+   * - Calling offer before the [[CompletionStage]] is completed, in this case it will return a failed [[CompletionStage]]
    *
    * @param elem element to send to a stream
    */
   def offer(elem: T): CompletionStage[QueueOfferResult]
 
   /**
-   * Method returns a [[CompletionStage]] that will be completed if this
+   * Returns a [[CompletionStage]] that will be completed if this
    * operator completes, or will be failed when the stream is failed.
    */
   def watchCompletion(): CompletionStage[Done]
@@ -44,7 +48,7 @@ trait SourceQueue[T] {
 trait SourceQueueWithComplete[T] extends SourceQueue[T] {
 
   /**
-   * Complete the stream normally. Use `watchCompletion` to be notified of this
+   * Completes the stream normally. Use `watchCompletion` to be notified of this
    * operation’s success.
    *
    * Note that this only means the elements have been passed downstream, not
@@ -53,7 +57,7 @@ trait SourceQueueWithComplete[T] extends SourceQueue[T] {
   def complete(): Unit
 
   /**
-   * Complete the stream with a failure. Use `watchCompletion` to be notified of this
+   * Completes the stream with a failure. Use `watchCompletion` to be notified of this
    * operation’s success.
    *
    * Note that this only means the elements have been passed downstream, not
@@ -69,17 +73,37 @@ trait SourceQueueWithComplete[T] extends SourceQueue[T] {
   override def watchCompletion(): CompletionStage[Done]
 }
 
+object SourceQueueWithComplete {
+
+  /**
+   * Converts the queue into a `scaladsl.SourceQueueWithComplete`
+   */
+  def asScala[T](queue: SourceQueueWithComplete[T]): akka.stream.scaladsl.SourceQueueWithComplete[T] = {
+    // would have been better to add `asScala` in SourceQueueWithComplete trait, but not doing
+    // that for backwards compatibility reasons
+    new akka.stream.scaladsl.SourceQueueWithComplete[T] {
+      def offer(elem: T): Future[QueueOfferResult] = queue.offer(elem).toScala
+
+      def watchCompletion(): Future[Done] = queue.watchCompletion().toScala
+
+      def complete(): Unit = queue.complete()
+
+      def fail(ex: Throwable): Unit = queue.fail(ex)
+    }
+  }
+}
+
 /**
- * Trait allows to have the queue as a sink for some stream.
- * "SinkQueue" pulls data from stream with backpressure mechanism.
+ * This trait allows to have a queue as a sink for a stream.
+ * A [[SinkQueue]] pulls data from stream with a backpressure mechanism.
  */
 trait SinkQueue[T] {
 
   /**
-   * Method pulls elements from stream and returns future that:
-   * - fails if stream is failed
-   * - completes with None in case if stream is completed
-   * - completes with `Some(element)` in case next element is available from stream.
+   * Pulls elements from the stream and returns a [[CompletionStage]] that:
+   * - fails if the stream is failed
+   * - completes with Empty in case the stream is completed
+   * - completes with `element` in case the next element is available from the stream.
    */
   def pull(): CompletionStage[Optional[T]]
 }
@@ -90,7 +114,26 @@ trait SinkQueue[T] {
 trait SinkQueueWithCancel[T] extends SinkQueue[T] {
 
   /**
-   * Cancel the stream.
+   * Cancels the stream. This method returns right away without waiting for actual finalizing the stream.
    */
   def cancel(): Unit
 }
+
+object SinkQueueWithCancel {
+
+  /**
+   * Converts the queue into a `scaladsl.SinkQueueWithCancel`
+   */
+  def asScala[T](queue: SinkQueueWithCancel[T]): akka.stream.scaladsl.SinkQueueWithCancel[T] = {
+    // would have been better to add `asScala` in SinkQueueWithCancel trait, but not doing
+    // that for backwards compatibility reasons
+    new akka.stream.scaladsl.SinkQueueWithCancel[T] {
+      import akka.dispatch.ExecutionContexts.{ sameThreadExecutionContext ⇒ same }
+
+      override def pull(): Future[Option[T]] =
+        queue.pull().toScala.map(_.asScala)(same)
+
+      override def cancel(): Unit = queue.cancel()
+    }
+  }
+}
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
index 9afc1f6116..37d3420952 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
@@ -10,7 +10,7 @@ import akka.{ japi, Done, NotUsed }
 import akka.actor.{ ActorRef, Props }
 import akka.dispatch.ExecutionContexts
 import akka.japi.function
-import akka.stream.impl.{ LinearTraversalBuilder, SinkQueueAdapter }
+import akka.stream.impl.LinearTraversalBuilder
 import akka.stream.{ javadsl, scaladsl, _ }
 import org.reactivestreams.{ Publisher, Subscriber }
 
@@ -299,8 +299,8 @@ object Sink {
   }
 
   /**
-   * Creates a `Sink` that is materialized as an [[akka.stream.javadsl.SinkQueue]].
-   * [[akka.stream.javadsl.SinkQueue.pull]] method is pulling element from the stream and returns ``CompletionStage[Option[T]]``.
+   * Creates a `Sink` that is materialized as an [[akka.stream.javadsl.SinkQueueWithCancel]].
+   * [[akka.stream.javadsl.SinkQueueWithCancel.pull]] method is pulling element from the stream and returns ``CompletionStage[Option[T]]``.
    * `CompletionStage` completes when element is available.
    *
    * Before calling pull method second time you need to wait until previous CompletionStage completes.
@@ -310,13 +310,13 @@ object Sink {
    * upstream and then stop back pressure.  You can configure size of input
    * buffer by using [[Sink.withAttributes]] method.
    *
-   * For stream completion you need to pull all elements from [[akka.stream.javadsl.SinkQueue]] including last None
+   * For stream completion you need to pull all elements from [[akka.stream.javadsl.SinkQueueWithCancel]] including last None
    * as completion marker
    *
    * @see [[akka.stream.javadsl.SinkQueueWithCancel]]
    */
   def queue[T](): Sink[T, SinkQueueWithCancel[T]] =
-    new Sink(scaladsl.Sink.queue[T]().mapMaterializedValue(new SinkQueueAdapter(_)))
+    new Sink(scaladsl.Sink.queue[T]().mapMaterializedValue(_.asJava))
 
   /**
    * Creates a real `Sink` upon receiving the first element. Internal `Sink` will not be created if there are no elements,
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
index 9bf1d1b821..ded1962f7d 100755
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
@@ -12,7 +12,7 @@ import akka.annotation.ApiMayChange
 import akka.event.LoggingAdapter
 import akka.japi.{ function, Pair, Util }
 import akka.stream._
-import akka.stream.impl.{ LinearTraversalBuilder, SourceQueueAdapter }
+import akka.stream.impl.{ LinearTraversalBuilder }
 import akka.util.{ ConstantFun, Timeout }
 import akka.util.JavaDurationConverters._
 import akka.{ Done, NotUsed }
@@ -403,7 +403,7 @@ object Source {
   }
 
   /**
-   * Creates a `Source` that is materialized as an [[akka.stream.javadsl.SourceQueue]].
+   * Creates a `Source` that is materialized as an [[akka.stream.javadsl.SourceQueueWithComplete]].
    * You can push elements to the queue and they will be emitted to the stream if there is demand from downstream,
    * otherwise they will be buffered until request for demand is received. Elements in the buffer will be discarded
    * if downstream is terminated.
@@ -412,7 +412,7 @@ object Source {
    * there is no space available in the buffer.
    *
    * Acknowledgement mechanism is available.
-   * [[akka.stream.javadsl.SourceQueue.offer]] returns `CompletionStage<QueueOfferResult>` which completes with
+   * [[akka.stream.javadsl.SourceQueueWithComplete.offer]] returns `CompletionStage<QueueOfferResult>` which completes with
    * `QueueOfferResult.enqueued` if element was added to buffer or sent downstream. It completes with
    * `QueueOfferResult.dropped` if element was dropped. Can also complete with `QueueOfferResult.Failure` -
    * when stream failed or `QueueOfferResult.QueueClosed` when downstream is completed.
@@ -420,7 +420,7 @@ object Source {
    * The strategy [[akka.stream.OverflowStrategy.backpressure]] will not complete last `offer():CompletionStage`
    * call when buffer is full.
    *
-   * You can watch accessibility of stream with [[akka.stream.javadsl.SourceQueue.watchCompletion]].
+   * You can watch accessibility of stream with [[akka.stream.javadsl.SourceQueueWithComplete.watchCompletion]].
    * It returns a future that completes with success when this operator is completed or fails when stream is failed.
    *
    * The buffer can be disabled by using `bufferSize` of 0 and then received message will wait
@@ -433,7 +433,7 @@ object Source {
    * @param overflowStrategy Strategy that is used when incoming elements cannot fit inside the buffer
    */
   def queue[T](bufferSize: Int, overflowStrategy: OverflowStrategy): Source[T, SourceQueueWithComplete[T]] =
-    new Source(scaladsl.Source.queue[T](bufferSize, overflowStrategy).mapMaterializedValue(new SourceQueueAdapter(_)))
+    new Source(scaladsl.Source.queue[T](bufferSize, overflowStrategy).mapMaterializedValue(_.asJava))
 
   /**
    * Start a new `Source` from some resource which can be opened, read and closed.
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Queue.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Queue.scala
index 2bb5008b4e..c593d82d03 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Queue.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Queue.scala
@@ -4,33 +4,41 @@
 
 package akka.stream.scaladsl
 
+import java.util.Optional
+import java.util.concurrent.CompletionStage
+
 import scala.concurrent.Future
+
 import akka.Done
 import akka.stream.QueueOfferResult
+import scala.compat.java8.FutureConverters._
+import scala.compat.java8.OptionConverters._
+
+import akka.annotation.InternalApi
 
 /**
- * This trait allows to have the queue as a data source for some stream.
+ * This trait allows to have a queue as a data source for some stream.
  */
 trait SourceQueue[T] {
 
   /**
-   * Method offers next element to a stream and returns future that:
-   * - completes with `Enqueued` if element is consumed by a stream
-   * - completes with `Dropped` when stream dropped offered element
-   * - completes with `QueueClosed` when stream is completed during future is active
-   * - completes with `Failure(f)` when failure to enqueue element from upstream
-   * - fails when stream is completed
+   * Offers an element to a stream and returns a [[Future]] that:
+   * - completes with `Enqueued` if the element is consumed by a stream
+   * - completes with `Dropped` when the stream dropped the offered element
+   * - completes with `QueueClosed` when the stream is completed whilst the [[Future]] is active
+   * - completes with `Failure(f)` in case of failure to enqueue element from upstream
+   * - fails when stream is already completed
    *
    * Additionally when using the backpressure overflowStrategy:
-   * - If the buffer is full the Future won't be completed until there is space in the buffer
-   * - Calling offer before the Future is completed in this case will return a failed Future
+   * - If the buffer is full the [[Future]] won't be completed until there is space in the buffer
+   * - Calling offer before the [[Future]] is completed, in this case it will return a failed [[Future]]
    *
    * @param elem element to send to a stream
    */
   def offer(elem: T): Future[QueueOfferResult]
 
   /**
-   * Method returns a [[Future]] that will be completed if this operator
+   * Returns a [[Future]] that will be completed if this operator
    * completes, or will be failed when the operator faces an internal failure.
    *
    * Note that this only means the elements have been passed downstream, not
@@ -45,7 +53,7 @@ trait SourceQueue[T] {
 trait SourceQueueWithComplete[T] extends SourceQueue[T] {
 
   /**
-   * Complete the stream normally. Use `watchCompletion` to be notified of this
+   * Completes the stream normally. Use `watchCompletion` to be notified of this
    * operation’s success.
    *
    * Note that this only means the elements have been passed downstream, not
@@ -54,7 +62,7 @@ trait SourceQueueWithComplete[T] extends SourceQueue[T] {
   def complete(): Unit
 
   /**
-   * Complete the stream with a failure. Use `watchCompletion` to be notified of this
+   * Completes the stream with a failure. Use `watchCompletion` to be notified of this
    * operation’s success.
    */
   def fail(ex: Throwable): Unit
@@ -70,17 +78,44 @@ trait SourceQueueWithComplete[T] extends SourceQueue[T] {
   def watchCompletion(): Future[Done]
 }
 
+object SourceQueueWithComplete {
+  final implicit class QueueOps[T](val queue: SourceQueueWithComplete[T]) extends AnyVal {
+    // would have been better to add `asJava` in SourceQueueWithComplete trait, but not doing
+    // that for backwards compatibility reasons
+
+    /**
+     * Converts the queue into a `javadsl.SourceQueueWithComplete`
+     */
+    def asJava: akka.stream.javadsl.SourceQueueWithComplete[T] =
+      SourceQueueWithComplete.asJava(queue)
+  }
+
+  /**
+   * INTERNAL API: Converts the queue into a `javadsl.SourceQueueWithComplete`
+   */
+  @InternalApi private[akka] def asJava[T](
+      queue: SourceQueueWithComplete[T]): akka.stream.javadsl.SourceQueueWithComplete[T] =
+    new akka.stream.javadsl.SourceQueueWithComplete[T] {
+      def offer(elem: T): CompletionStage[QueueOfferResult] =
+        queue.offer(elem).toJava
+      def watchCompletion(): CompletionStage[Done] =
+        queue.watchCompletion().toJava
+      def complete(): Unit = queue.complete()
+      def fail(ex: Throwable): Unit = queue.fail(ex)
+    }
+}
+
 /**
- * Trait allows to have the queue as a sink for some stream.
- * "SinkQueue" pulls data from stream with backpressure mechanism.
+ * This trait allows to have a queue as a sink for a stream.
+ * A [[SinkQueue]] pulls data from a stream with a backpressure mechanism.
  */
 trait SinkQueue[T] {
 
   /**
-   * Method pulls elements from stream and returns future that:
-   * - fails if stream is failed
-   * - completes with None in case if stream is completed
-   * - completes with `Some(element)` in case next element is available from stream.
+   * Pulls elements from the stream and returns a [[Future]] that:
+   * - fails if the stream is failed
+   * - completes with None in case the stream is completed
+   * - completes with `Some(element)` in case the next element is available from stream.
    */
   def pull(): Future[Option[T]]
 }
@@ -91,7 +126,28 @@ trait SinkQueue[T] {
 trait SinkQueueWithCancel[T] extends SinkQueue[T] {
 
   /**
-   * Cancel the stream. This method returns right away without waiting for actual finalizing stream.
+   * Cancels the stream. This method returns right away without waiting for actual finalizing the stream.
    */
   def cancel(): Unit
 }
+
+object SinkQueueWithCancel {
+  final implicit class QueueOps[T](val queue: SinkQueueWithCancel[T]) extends AnyVal {
+    // would have been better to add `asJava` in SinkQueueWithCancel trait, but not doing
+    // that for backwards compatibility reasons
+
+    def asJava: akka.stream.javadsl.SinkQueueWithCancel[T] =
+      SinkQueueWithCancel.asJava(queue)
+  }
+
+  /**
+   * INTERNAL API: Converts the queue into a `javadsl.SinkQueueWithCancel`
+   */
+  @InternalApi private[akka] def asJava[T](queue: SinkQueueWithCancel[T]): akka.stream.javadsl.SinkQueueWithCancel[T] =
+    new akka.stream.javadsl.SinkQueueWithCancel[T] {
+      import akka.dispatch.ExecutionContexts.{ sameThreadExecutionContext ⇒ same }
+      override def pull(): CompletionStage[Optional[T]] =
+        queue.pull().map(_.asJava)(same).toJava
+      override def cancel(): Unit = queue.cancel()
+    }
+}
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
index 93a282f9f8..fe7420687a 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
@@ -533,8 +533,8 @@ object Sink {
   }
 
   /**
-   * Creates a `Sink` that is materialized as an [[akka.stream.scaladsl.SinkQueue]].
-   * [[akka.stream.scaladsl.SinkQueue.pull]] method is pulling element from the stream and returns ``Future[Option[T]]``.
+   * Creates a `Sink` that is materialized as an [[akka.stream.scaladsl.SinkQueueWithCancel]].
+   * [[akka.stream.scaladsl.SinkQueueWithCancel.pull]] method is pulling element from the stream and returns ``Future[Option[T]]``.
    * `Future` completes when element is available.
    *
    * Before calling pull method second time you need to wait until previous Future completes.
@@ -544,7 +544,7 @@ object Sink {
    * upstream and then stop back pressure.  You can configure size of input
    * buffer by using [[Sink.withAttributes]] method.
    *
-   * For stream completion you need to pull all elements from [[akka.stream.scaladsl.SinkQueue]] including last None
+   * For stream completion you need to pull all elements from [[akka.stream.scaladsl.SinkQueueWithCancel]] including last None
    * as completion marker
    *
    * See also [[akka.stream.scaladsl.SinkQueueWithCancel]]
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index a438fb3da4..28a2ed9c27 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -615,7 +615,7 @@ object Source {
   }
 
   /**
-   * Creates a `Source` that is materialized as an [[akka.stream.scaladsl.SourceQueue]].
+   * Creates a `Source` that is materialized as an [[akka.stream.scaladsl.SourceQueueWithComplete]].
    * You can push elements to the queue and they will be emitted to the stream if there is demand from downstream,
    * otherwise they will be buffered until request for demand is received. Elements in the buffer will be discarded
    * if downstream is terminated.
@@ -624,7 +624,7 @@ object Source {
    * there is no space available in the buffer.
    *
    * Acknowledgement mechanism is available.
-   * [[akka.stream.scaladsl.SourceQueue.offer]] returns `Future[QueueOfferResult]` which completes with
+   * [[akka.stream.scaladsl.SourceQueueWithComplete.offer]] returns `Future[QueueOfferResult]` which completes with
    * `QueueOfferResult.Enqueued` if element was added to buffer or sent downstream. It completes with
    * `QueueOfferResult.Dropped` if element was dropped. Can also complete  with `QueueOfferResult.Failure` -
    * when stream failed or `QueueOfferResult.QueueClosed` when downstream is completed.
@@ -632,7 +632,7 @@ object Source {
    * The strategy [[akka.stream.OverflowStrategy.backpressure]] will not complete last `offer():Future`
    * call when buffer is full.
    *
-   * You can watch accessibility of stream with [[akka.stream.scaladsl.SourceQueue.watchCompletion]].
+   * You can watch accessibility of stream with [[akka.stream.scaladsl.SourceQueueWithComplete.watchCompletion]].
    * It returns future that completes with success when the operator is completed or fails when the stream is failed.
    *
    * The buffer can be disabled by using `bufferSize` of 0 and then received message will wait