diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java
index 03d1f219a8..5fac956e12 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java
@@ -257,7 +257,7 @@ public class BidiFlowTest extends StreamTest {
           }
         });
     final Pair<Pair<Future<Integer>, Future<Integer>>, Future<List<Long>>> result =
-        left.join(bidiMat, Keep.<Future<Integer>, Future<Integer>> both()).join(right, Keep.<Pair<Future<Integer>, Future<Integer>>, Future<List<Long>>> both()).run(materializer);
+        left.joinMat(bidiMat, Keep.<Future<Integer>, Future<Integer>> both()).joinMat(right, Keep.<Pair<Future<Integer>, Future<Integer>>, Future<List<Long>>> both()).run(materializer);
     final Future<Integer> l = result.first().first();
     final Future<Integer> m = result.first().second();
     final Future<List<Long>> r = result.second();
diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/TcpTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/TcpTest.java
index 5ec4a5b6c9..cc226ebe77 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/TcpTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/TcpTest.java
@@ -31,14 +31,14 @@ public class TcpTest extends StreamTest {
   @ClassRule
   public static AkkaJUnitActorSystemResource actorSystemResource = new AkkaJUnitActorSystemResource("TcpTest",
     AkkaSpec.testConf());
-  
+
   final Sink<IncomingConnection, Future<BoxedUnit>> echoHandler =
       Sink.foreach(new Procedure<IncomingConnection>() {
         public void apply(IncomingConnection conn) {
           conn.handleWith(Flow.<ByteString>empty(), materializer);
         }
       });
-  
+
   final List<ByteString> testInput = new ArrayList<ByteString>();
   {
     for (char c = 'a'; c <= 'z'; c++) {
@@ -51,34 +51,34 @@ public class TcpTest extends StreamTest {
     final InetSocketAddress serverAddress = TestUtils.temporaryServerAddress("127.0.0.1", false);
     final Source<IncomingConnection, Future<ServerBinding>> binding = Tcp.get(system)
         .bind(serverAddress.getHostName(), serverAddress.getPort()); // TODO getHostString in Java7
-    
+
     final Future<ServerBinding> future = binding.to(echoHandler).run(materializer);
     final ServerBinding b = Await.result(future, FiniteDuration.create(5, TimeUnit.SECONDS));
     assertEquals(b.localAddress().getPort(), serverAddress.getPort());
-    
+
     final Future<ByteString> resultFuture = Source
         .from(testInput)
         // TODO getHostString in Java7
-        .via(Tcp.get(system).outgoingConnection(serverAddress.getHostName(), serverAddress.getPort())) 
+        .via(Tcp.get(system).outgoingConnection(serverAddress.getHostName(), serverAddress.getPort()))
         .runFold(ByteString.empty(),
             new Function2<ByteString, ByteString, ByteString>() {
               public ByteString apply(ByteString acc, ByteString elem) {
                 return acc.concat(elem);
               }
             }, materializer);
-    
+
     final byte[] result = Await.result(resultFuture, FiniteDuration.create(5, TimeUnit.SECONDS)).toArray();
     for (int i = 0; i < testInput.size(); i ++) {
-      assertEquals(testInput.get(i).head(), result[i]);  
+      assertEquals(testInput.get(i).head(), result[i]);
     }
   }
-  
+
   @Test
   public void mustReportServerBindFailure() throws Exception {
     final InetSocketAddress serverAddress = TestUtils.temporaryServerAddress("127.0.0.1", false);
     final Source<IncomingConnection, Future<ServerBinding>> binding = Tcp.get(system)
         .bind(serverAddress.getHostName(), serverAddress.getPort()); // TODO getHostString in Java7
-    
+
     final Future<ServerBinding> future = binding.to(echoHandler).run(materializer);
     final ServerBinding b = Await.result(future, FiniteDuration.create(5, TimeUnit.SECONDS));
     assertEquals(b.localAddress().getPort(), serverAddress.getPort());
@@ -90,7 +90,7 @@ public class TcpTest extends StreamTest {
       // expected
     }
   }
-  
+
   @Test
   public void mustReportClientConnectFailure() throws Exception {
     final InetSocketAddress serverAddress = TestUtils.temporaryServerAddress(
@@ -99,7 +99,7 @@ public class TcpTest extends StreamTest {
       Await.result(
           Source.from(testInput)
               // TODO getHostString in Java7
-              .via(Tcp.get(system).outgoingConnection(serverAddress.getHostName(), serverAddress.getPort()), 
+              .viaMat(Tcp.get(system).outgoingConnection(serverAddress.getHostName(), serverAddress.getPort()),
                   Keep.<BoxedUnit, Future<OutgoingConnection>> right())
               .to(Sink.<ByteString> ignore())
               .run(materializer),
diff --git a/akka-stream-tests/src/test/scala/akka/stream/DslConsistencySpec.scala b/akka-stream-tests/src/test/scala/akka/stream/DslConsistencySpec.scala
index 2d27175a57..c6f2170264 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/DslConsistencySpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/DslConsistencySpec.scala
@@ -24,7 +24,8 @@ class DslConsistencySpec extends WordSpec with Matchers {
 
   val ignore =
     Set("equals", "hashCode", "notify", "notifyAll", "wait", "toString", "getClass") ++
-      Set("create", "apply", "ops", "appendJava", "andThen", "withAttributes") ++
+      Set("productArity", "canEqual", "productPrefix", "copy", "productIterator", "productElement") ++
+      Set("create", "apply", "ops", "appendJava", "andThen", "andThenMat", "isIdentity", "withAttributes", "transformMaterializing") ++
       Set("asScala", "asJava")
 
   val allowMissing: Map[Class[_], Set[String]] = Map(
@@ -58,7 +59,6 @@ class DslConsistencySpec extends WordSpec with Matchers {
         case (element, classes) ⇒
 
           s"provide same $element transforming operators" in {
-            pending
             val allOps =
               (for {
                 c ← classes
@@ -74,7 +74,6 @@ class DslConsistencySpec extends WordSpec with Matchers {
           }
 
           s"provide same $element materializing operators" in {
-            pending
             val materializingOps =
               (for {
                 c ← classes
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
index 8ef7531f37..eb25d765c7 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
@@ -79,7 +79,7 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
   /**
    * Transform this [[Flow]] by appending the given processing steps.
    */
-  def via[T, M, M2](flow: Graph[FlowShape[Out, T], M], combine: function.Function2[Mat, M, M2]): javadsl.Flow[In, T, M2] =
+  def viaMat[T, M, M2](flow: Graph[FlowShape[Out, T], M], combine: function.Function2[Mat, M, M2]): javadsl.Flow[In, T, M2] =
     new Flow(delegate.viaMat(flow)(combinerToScala(combine)))
 
   /**
@@ -91,7 +91,7 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
   /**
    * Connect this [[Flow]] to a [[Sink]], concatenating the processing steps of both.
    */
-  def to[M, M2](sink: Graph[SinkShape[Out], M], combine: function.Function2[Mat, M, M2]): javadsl.Sink[In, M2] =
+  def toMat[M, M2](sink: Graph[SinkShape[Out], M], combine: function.Function2[Mat, M, M2]): javadsl.Sink[In, M2] =
     new Sink(delegate.toMat(sink)(combinerToScala(combine)))
 
   /**
@@ -103,7 +103,7 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
   /**
    * Join this [[Flow]] to another [[Flow]], by cross connecting the inputs and outputs, creating a [[RunnableFlow]]
    */
-  def join[M, M2](flow: Graph[FlowShape[Out, In], M], combine: function.Function2[Mat, M, M2]): javadsl.RunnableFlow[M2] =
+  def joinMat[M, M2](flow: Graph[FlowShape[Out, In], M], combine: function.Function2[Mat, M, M2]): javadsl.RunnableFlow[M2] =
     new RunnableFlowAdapter(delegate.joinMat(flow)(combinerToScala(combine)))
 
   /**
@@ -142,7 +142,7 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
    * The `combine` function is used to compose the materialized values of this flow and that
    * [[BidiFlow]] into the materialized value of the resulting [[Flow]].
    */
-  def join[I2, O2, Mat2, M](bidi: Graph[BidiShape[Out, O2, I2, In], Mat2], combine: function.Function2[Mat, Mat2, M]): Flow[I2, O2, M] =
+  def joinMat[I2, O2, Mat2, M](bidi: Graph[BidiShape[Out, O2, I2, In], Mat2], combine: function.Function2[Mat, Mat2, M]): Flow[I2, O2, M] =
     new Flow(delegate.joinMat(bidi)(combinerToScala(combine)))
 
   /**
@@ -680,11 +680,27 @@ class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends Graph
     new Flow(delegate.flatten(strategy))
 
   /**
-   * Returns a new `Flow` that concatenates a secondary `Source` to this flow so that,
-   * the first element emitted by the given ("second") source is emitted after the last element of this Flow.
+   * Concatenate the given [[Source]] to this [[Flow]], meaning that once this
+   * Flow’s input is exhausted and all result elements have been generated,
+   * the Source’s elements will be produced. Note that the Source is materialized
+   * together with this Flow and just kept from producing elements by asserting
+   * back-pressure until its time comes.
+   *
+   * The resulting Flow’s materialized value is a Pair containing both materialized
+   * values (of this Flow and that Source).
    */
-  def concat[M](second: Graph[SourceShape[Out @uncheckedVariance], M]): javadsl.Flow[In, Out, Mat @uncheckedVariance Pair M] =
-    new Flow(delegate.concat(second).mapMaterializedValue(p ⇒ Pair(p._1, p._2)))
+  def concat[M](source: Graph[SourceShape[Out @uncheckedVariance], M]): javadsl.Flow[In, Out, Mat @uncheckedVariance Pair M] =
+    new Flow(delegate.concat(source).mapMaterializedValue(p ⇒ Pair(p._1, p._2)))
+
+  /**
+   * Concatenate the given [[Source]] to this [[Flow]], meaning that once this
+   * Flow’s input is exhausted and all result elements have been generated,
+   * the Source’s elements will be produced. Note that the Source is materialized
+   * together with this Flow and just kept from producing elements by asserting
+   * back-pressure until its time comes.
+   */
+  def concatMat[M, M2](source: Graph[SourceShape[Out @uncheckedVariance], M], combine: function.Function2[Mat, M, M2]): javadsl.Flow[In, Out, M2] =
+    new Flow(delegate.concatMat(source)(combinerToScala(combine)))
 
   override def withAttributes(attr: OperationAttributes): javadsl.Flow[In, Out, Mat] =
     new Flow(delegate.withAttributes(attr))
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 9c600c47fa..d30a020790 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
@@ -254,7 +254,7 @@ class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Graph[Sour
   /**
    * Transform this [[Source]] by appending the given processing stages.
    */
-  def via[T, M, M2](flow: Graph[FlowShape[Out, T], M], combine: function.Function2[Mat, M, M2]): javadsl.Source[T, M2] =
+  def viaMat[T, M, M2](flow: Graph[FlowShape[Out, T], M], combine: function.Function2[Mat, M, M2]): javadsl.Source[T, M2] =
     new Source(delegate.viaMat(flow)(combinerToScala(combine)))
 
   /**
@@ -266,7 +266,7 @@ class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Graph[Sour
   /**
    * Connect this [[Source]] to a [[Sink]], concatenating the processing steps of both.
    */
-  def to[M, M2](sink: Graph[SinkShape[Out], M], combine: function.Function2[Mat, M, M2]): javadsl.RunnableFlow[M2] =
+  def toMat[M, M2](sink: Graph[SinkShape[Out], M], combine: function.Function2[Mat, M, M2]): javadsl.RunnableFlow[M2] =
     new RunnableFlowAdapter(delegate.toMat(sink)(combinerToScala(combine)))
 
   /**
@@ -292,9 +292,17 @@ class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Graph[Sour
    * emitted by that source is emitted after the last element of this
    * source.
    */
-  def concat[Out2 >: Out, M2](second: Graph[SourceShape[Out2], M2]): Source[Out2, (Mat, M2)] =
+  def concat[Out2 >: Out, M2](second: Graph[SourceShape[Out2], M2]): javadsl.Source[Out2, (Mat, M2)] =
     Source.concat(this, second)
 
+  /**
+   * Concatenates a second source so that the first element
+   * emitted by that source is emitted after the last element of this
+   * source.
+   */
+  def concatMat[M, M2](second: Graph[SourceShape[Out @uncheckedVariance], M], combine: function.Function2[Mat, M, M2]): javadsl.Source[Out, M2] =
+    new Source(delegate.concatMat(second)(combinerToScala(combine)))
+
   /**
    * Shortcut for running this `Source` with a foreach procedure. The given procedure is invoked
    * for each received element.