diff --git a/instrumentation/kamon-apache-cxf/src/main/scala/kamon/instrumentation/apache/cxf/client/ApacheCxfClientHelper.scala b/instrumentation/kamon-apache-cxf/src/main/scala/kamon/instrumentation/apache/cxf/client/ApacheCxfClientHelper.scala
index 04cbeef17..6054366ea 100644
--- a/instrumentation/kamon-apache-cxf/src/main/scala/kamon/instrumentation/apache/cxf/client/ApacheCxfClientHelper.scala
+++ b/instrumentation/kamon-apache-cxf/src/main/scala/kamon/instrumentation/apache/cxf/client/ApacheCxfClientHelper.scala
@@ -9,7 +9,7 @@ import java.net.{URI, URISyntaxException}
 import java.util.Collections.{emptyMap => jEmptyMap, singletonList => jList}
 import java.util.{List => JList, Map => JMap}
 import scala.collection.mutable
-import scala.jdk.CollectionConverters.{ListHasAsScala, MapHasAsJava, MapHasAsScala}
+import scala.collection.JavaConverters._
 
 class ApacheCxfClientHelper
 
@@ -25,7 +25,9 @@ object ApacheCxfClientHelper {
       val uri: URI = getUri(request)
 
       override def write(header: String, value: String): Unit = {
-        val headers: mutable.Map[String, String] = getAllHeaders(delegate).to(mutable.Map)
+        val builder = mutable.Map.newBuilder[String, String]
+        builder ++= getAllHeaders(delegate)
+        val headers: mutable.Map[String, String] = builder.result()
         headers.put(header, value)
         delegate.put(Message.PROTOCOL_HEADERS, headers.map(m => m._1 -> jList(m._2)).toMap.asJava)
       }
diff --git a/instrumentation/kamon-apache-cxf/src/test/scala/kamon/instrumentation/apache/cxf/client/util/MockServerExpectations.scala b/instrumentation/kamon-apache-cxf/src/test/scala/kamon/instrumentation/apache/cxf/client/util/MockServerExpectations.scala
index 252e15d06..42d1062c5 100644
--- a/instrumentation/kamon-apache-cxf/src/test/scala/kamon/instrumentation/apache/cxf/client/util/MockServerExpectations.scala
+++ b/instrumentation/kamon-apache-cxf/src/test/scala/kamon/instrumentation/apache/cxf/client/util/MockServerExpectations.scala
@@ -8,7 +8,7 @@ import org.mockserver.model.HttpRequest.request
 import org.mockserver.model.HttpResponse.response
 import org.slf4j.LoggerFactory
 
-import scala.jdk.CollectionConverters.SeqHasAsJava
+import scala.collection.JavaConverters._
 
 class MockServerExpectations(private val host: String, private val port: Int) {