diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/OutgoingRoomKeyRequestManager.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/OutgoingRoomKeyRequestManager.kt
index 9436a39873..a13ae75bca 100755
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/OutgoingRoomKeyRequestManager.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/crypto/OutgoingRoomKeyRequestManager.kt
@@ -31,7 +31,6 @@ import im.vector.matrix.android.internal.task.TaskThread
 import im.vector.matrix.android.internal.task.configureWith
 import im.vector.matrix.android.internal.util.createBackgroundHandler
 import timber.log.Timber
-import java.util.*
 import java.util.concurrent.atomic.AtomicBoolean
 import javax.inject.Inject
 
@@ -185,9 +184,9 @@ internal class OutgoingRoomKeyRequestManager @Inject constructor(
 
         Timber.v("## sendOutgoingRoomKeyRequests() :  Looking for queued outgoing room key requests")
         val outgoingRoomKeyRequest = cryptoStore.getOutgoingRoomKeyRequestByState(
-                HashSet<OutgoingRoomKeyRequest.RequestState>(Arrays.asList<OutgoingRoomKeyRequest.RequestState>(OutgoingRoomKeyRequest.RequestState.UNSENT,
+                setOf(OutgoingRoomKeyRequest.RequestState.UNSENT,
                         OutgoingRoomKeyRequest.RequestState.CANCELLATION_PENDING,
-                        OutgoingRoomKeyRequest.RequestState.CANCELLATION_PENDING_AND_WILL_RESEND)))
+                        OutgoingRoomKeyRequest.RequestState.CANCELLATION_PENDING_AND_WILL_RESEND))
 
         if (null == outgoingRoomKeyRequest) {
             Timber.e("## sendOutgoingRoomKeyRequests() : No more outgoing room key requests")
diff --git a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/state/DefaultStateService.kt b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/state/DefaultStateService.kt
index 053bf7f7a6..e51f9b466a 100644
--- a/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/state/DefaultStateService.kt
+++ b/matrix-sdk-android/src/main/java/im/vector/matrix/android/internal/session/room/state/DefaultStateService.kt
@@ -30,9 +30,9 @@ internal class DefaultStateService @Inject constructor(private val roomId: Strin
     override fun updateTopic(topic: String, callback: MatrixCallback<Unit>) {
         val params = SendStateTask.Params(roomId,
                 EventType.STATE_ROOM_TOPIC,
-                HashMap<String, String>().apply {
-                    put("topic", topic)
-                })
+                mapOf(
+                        "topic" to topic
+                ))
 
 
         sendStateTask.configureWith(params)
diff --git a/tools/check/forbidden_strings_in_code.txt b/tools/check/forbidden_strings_in_code.txt
index 08e2e0d08e..7361e5f8a2 100644
--- a/tools/check/forbidden_strings_in_code.txt
+++ b/tools/check/forbidden_strings_in_code.txt
@@ -50,7 +50,7 @@ succes[^s]
 ### Use int instead of Integer
 protected Integer
 
-### Use the interface declaration. Example: use type "Map" instead of type "HashMap" to declare variable or parameter
+### Use the interface declaration. Example: use type "Map" instead of type "HashMap" to declare variable or parameter. For Kotlin, use mapOf, setOf, ...
 (private|public|protected|    ) (static )?(final )?(HashMap|HashSet|ArrayList)<
 
 ### Use int instead of short