diff --git a/http/src/main/scala/org/apache/pekko/http/javadsl/unmarshalling/Unmarshaller.scala b/http/src/main/scala/org/apache/pekko/http/javadsl/unmarshalling/Unmarshaller.scala
index 7c20d377d..5a20c42e9 100644
--- a/http/src/main/scala/org/apache/pekko/http/javadsl/unmarshalling/Unmarshaller.scala
+++ b/http/src/main/scala/org/apache/pekko/http/javadsl/unmarshalling/Unmarshaller.scala
@@ -14,6 +14,7 @@
 package org.apache.pekko.http.javadsl.unmarshalling
 
 import java.util.concurrent.CompletionStage
+import java.util.Optional
 
 import org.apache.pekko
 import pekko.actor.ClassicActorSystemProvider
@@ -21,14 +22,12 @@ import pekko.annotation.InternalApi
 import pekko.http.impl.model.JavaQuery
 import pekko.http.impl.util.JavaMapping
 import pekko.http.impl.util.JavaMapping.Implicits._
-import pekko.http.javadsl.model._
+import pekko.http.{ javadsl => jm }
+import jm.model._
 import pekko.http.scaladsl.model.{ ContentTypeRange, ContentTypes }
 import pekko.http.scaladsl.unmarshalling
 import pekko.http.scaladsl.unmarshalling.FromEntityUnmarshaller
-import pekko.http.scaladsl.unmarshalling.Unmarshaller.{
-  EnhancedFromEntityUnmarshaller,
-  UnsupportedContentTypeException
-}
+import pekko.http.scaladsl.unmarshalling.Unmarshaller.EnhancedFromEntityUnmarshaller
 import pekko.http.scaladsl.util.FastFuture
 import pekko.stream.{ Materializer, SystemMaterializer }
 import pekko.util.ByteString
@@ -79,6 +78,7 @@ object Unmarshaller extends pekko.http.javadsl.unmarshalling.Unmarshallers {
     unmarshalling.Unmarshaller.strict[HttpRequest, RequestEntity](_.entity)
 
   def forMediaType[B](t: MediaType, um: Unmarshaller[HttpEntity, B]): Unmarshaller[HttpEntity, B] = {
+    import pekko.http.scaladsl.unmarshalling.Unmarshaller.UnsupportedContentTypeException
     unmarshalling.Unmarshaller.withMaterializer[HttpEntity, B] { implicit ex => implicit mat => jEntity =>
       {
         val entity = jEntity.asScala
@@ -124,6 +124,40 @@ object Unmarshaller extends pekko.http.javadsl.unmarshalling.Unmarshallers {
       implicit mi: JavaMapping[JI, SI]): unmarshalling.Unmarshaller[JI, O] =
     um.asInstanceOf[unmarshalling.Unmarshaller[JI, O]] // since guarantee provided by existence of `mi`
 
+  class UnsupportedContentTypeException(
+      private val _supported: java.util.Set[jm.model.ContentTypeRange],
+      private val _actualContentType: Optional[jm.model.ContentType])
+      extends RuntimeException(_supported.asScala.mkString(
+        s"Unsupported Content-Type [${_actualContentType.asScala}], supported: ", ", ", "")) {
+
+    def this(supported: jm.model.ContentTypeRange*) = {
+      this(supported.toSet.asJava, Optional.empty[jm.model.ContentType]())
+    }
+
+    def this(supported: java.util.Set[jm.model.ContentTypeRange]) = {
+      this(supported, Optional.empty[jm.model.ContentType]())
+    }
+
+    def this(contentType: Optional[jm.model.ContentType], supported: jm.model.ContentTypeRange*) = {
+      this(supported.toSet.asJava, contentType)
+    }
+
+    def toScala(): pekko.http.scaladsl.unmarshalling.Unmarshaller.UnsupportedContentTypeException =
+      pekko.http.scaladsl.unmarshalling.Unmarshaller.UnsupportedContentTypeException(
+        _supported.asScala.toSet.asInstanceOf[Set[pekko.http.scaladsl.model.ContentTypeRange]],
+        _actualContentType.asScala)
+
+    def getSupported(): java.util.Set[jm.model.ContentTypeRange] = _supported
+
+    def getActualContentType(): Optional[jm.model.ContentType] = _actualContentType
+
+    override def equals(that: Any): Boolean = that match {
+      case that: UnsupportedContentTypeException =>
+        that._supported == this._supported && that._actualContentType == this._actualContentType
+      case _ => false
+    }
+  }
+
 }
 
 trait UnmarshallerBase[-A, B]
diff --git a/http/src/main/scala/org/apache/pekko/http/scaladsl/unmarshalling/Unmarshaller.scala b/http/src/main/scala/org/apache/pekko/http/scaladsl/unmarshalling/Unmarshaller.scala
index 2385d2f06..2743f9859 100644
--- a/http/src/main/scala/org/apache/pekko/http/scaladsl/unmarshalling/Unmarshaller.scala
+++ b/http/src/main/scala/org/apache/pekko/http/scaladsl/unmarshalling/Unmarshaller.scala
@@ -15,15 +15,19 @@ package org.apache.pekko.http.scaladsl.unmarshalling
 
 import org.apache.pekko
 import pekko.event.Logging
+import pekko.http.{ javadsl => jm }
 import pekko.http.scaladsl.model._
 import pekko.http.scaladsl.util.FastFuture
 import pekko.http.scaladsl.util.FastFuture._
+import pekko.http.impl.util.JavaMapping.Implicits._
 import pekko.stream.Materializer
+import pekko.util.OptionConverters._
 
+import scala.collection.JavaConverters._
 import scala.concurrent.{ ExecutionContext, Future }
 import scala.util.control.{ NoStackTrace, NonFatal }
 
-trait Unmarshaller[-A, B] extends pekko.http.javadsl.unmarshalling.Unmarshaller[A, B] {
+trait Unmarshaller[-A, B] extends jm.unmarshalling.Unmarshaller[A, B] {
 
   implicit final def asScala: Unmarshaller[A, B] = this
 
@@ -164,21 +168,29 @@ object Unmarshaller
    * [[pekko.http.scaladsl.unmarshalling.Unmarshaller]] instead.
    */
   final class UnsupportedContentTypeException(
-      val supported: Set[ContentTypeRange],
-      val actualContentType: Option[ContentType])
-      extends RuntimeException(supported.mkString(
-        s"Unsupported Content-Type [$actualContentType], supported: ", ", ", "")) with Product with Serializable {
+      private val _supported: java.util.Set[jm.model.ContentTypeRange],
+      private val _actualContentType: java.util.Optional[jm.model.ContentType])
+      extends jm.unmarshalling.Unmarshaller.UnsupportedContentTypeException(_supported, _actualContentType) with Product
+      with Serializable {
+
+    val supported: Set[ContentTypeRange] =
+      _supported.asScala.toSet.asInstanceOf[Set[pekko.http.scaladsl.model.ContentTypeRange]]
+    val actualContentType: Option[ContentType] = _actualContentType.asScala
+
+    def this(supported: Set[ContentTypeRange], actualContentType: Option[ContentType]) =
+      this(supported.asJava.asInstanceOf[java.util.Set[jm.model.ContentTypeRange]],
+        actualContentType.toJava.asInstanceOf[java.util.Optional[jm.model.ContentType]])
 
     @deprecated("for binary compatibility", since = "Akka HTTP 10.1.9")
     def this(supported: Set[ContentTypeRange]) = this(supported, None)
 
     @deprecated("for binary compatibility", since = "Akka HTTP 10.1.9")
     def copy(supported: Set[ContentTypeRange]): UnsupportedContentTypeException =
-      new UnsupportedContentTypeException(supported, this.actualContentType)
+      new UnsupportedContentTypeException(supported, actualContentType)
 
     @deprecated("for binary compatibility", since = "Akka HTTP 10.1.9")
     def copy$default$1(supported: Set[ContentTypeRange]): UnsupportedContentTypeException =
-      new UnsupportedContentTypeException(supported, this.actualContentType)
+      new UnsupportedContentTypeException(supported, actualContentType)
 
     @deprecated("for binary compatibility", since = "Akka HTTP 10.1.9")
     def copy(
@@ -190,7 +202,7 @@ object Unmarshaller
 
     override def equals(that: Any): Boolean = that match {
       case that: UnsupportedContentTypeException =>
-        that.canEqual(this) && that.supported == this.supported && that.actualContentType == this.actualContentType
+        that.canEqual(this) && super.equals(this)
       case _ => false
     }
     override def productArity: Int = 1