diff --git a/akka-projection-dynamodb-integration/src/test/scala/akka/projection/dynamodb/DynamoDBTimestampOffsetProjectionSpec.scala b/akka-projection-dynamodb-integration/src/test/scala/akka/projection/dynamodb/DynamoDBTimestampOffsetProjectionSpec.scala
index 617a5ad29..1e5baa90d 100644
--- a/akka-projection-dynamodb-integration/src/test/scala/akka/projection/dynamodb/DynamoDBTimestampOffsetProjectionSpec.scala
+++ b/akka-projection-dynamodb-integration/src/test/scala/akka/projection/dynamodb/DynamoDBTimestampOffsetProjectionSpec.scala
@@ -6,11 +6,14 @@ package akka.projection.dynamodb
 
 import java.time.Instant
 import java.time.{ Duration => JDuration }
+import java.util.Optional
 import java.util.UUID
 import java.util.concurrent.CompletionException
+import java.util.concurrent.CompletionStage
 import java.util.concurrent.ConcurrentHashMap
 import java.util.concurrent.atomic.AtomicBoolean
 import java.util.concurrent.atomic.AtomicInteger
+import java.util.function.Supplier
 import java.util.{ HashMap => JHashMap }
 
 import scala.annotation.tailrec
@@ -20,7 +23,9 @@ import scala.concurrent.ExecutionContext
 import scala.concurrent.Future
 import scala.concurrent.duration._
 import scala.jdk.CollectionConverters._
+import scala.jdk.DurationConverters._
 import scala.jdk.FutureConverters._
+import scala.jdk.OptionConverters._
 import scala.util.Failure
 import scala.util.Success
 
@@ -159,6 +164,68 @@ object DynamoDBTimestampOffsetProjectionSpec {
     }
   }
 
+  class JavaTestTimestampSourceProvider(
+      envelopes: immutable.IndexedSeq[EventEnvelope[String]],
+      testSourceProvider: akka.projection.testkit.javadsl.TestSourceProvider[Offset, EventEnvelope[String]],
+      override val maxSlice: Int,
+      enableCurrentEventsByPersistenceId: Boolean)
+      extends akka.projection.javadsl.SourceProvider[Offset, EventEnvelope[String]]
+      with BySlicesSourceProvider
+      with akka.persistence.query.typed.javadsl.EventTimestampQuery
+      with akka.persistence.query.typed.javadsl.LoadEventQuery
+      with LoadEventsByPersistenceIdSourceProvider[String] {
+
+    override def source(offset: Supplier[CompletionStage[Optional[Offset]]])
+        : CompletionStage[akka.stream.javadsl.Source[EventEnvelope[String], NotUsed]] =
+      testSourceProvider.source(offset)
+
+    override def extractOffset(envelope: EventEnvelope[String]): Offset =
+      testSourceProvider.extractOffset(envelope)
+
+    override def extractCreationTime(envelope: EventEnvelope[String]): Long =
+      testSourceProvider.extractCreationTime(envelope)
+
+    override def minSlice: Int = 0
+
+    override def timestampOf(persistenceId: String, sequenceNr: Long): CompletionStage[Optional[Instant]] = {
+      Future
+        .successful(envelopes.collectFirst {
+          case env
+              if env.persistenceId == persistenceId && env.sequenceNr == sequenceNr && env.offset
+                .isInstanceOf[TimestampOffset] =>
+            env.offset.asInstanceOf[TimestampOffset].timestamp
+        }.toJava)
+        .asJava
+    }
+
+    override def loadEnvelope[Event](persistenceId: String, sequenceNr: Long): CompletionStage[EventEnvelope[Event]] = {
+      envelopes.collectFirst {
+        case env if env.persistenceId == persistenceId && env.sequenceNr == sequenceNr =>
+          env.asInstanceOf[EventEnvelope[Event]]
+      } match {
+        case Some(env) => Future.successful(env).asJava
+        case None =>
+          Future
+            .failed(
+              new NoSuchElementException(
+                s"Event with persistenceId [$persistenceId] and sequenceNr [$sequenceNr] not found."))
+            .asJava
+      }
+    }
+
+    override private[akka] def currentEventsByPersistenceId(
+        persistenceId: String,
+        fromSequenceNr: Long,
+        toSequenceNr: Long): Option[Source[EventEnvelope[String], NotUsed]] = {
+      if (enableCurrentEventsByPersistenceId)
+        Some(Source(envelopes.filter { env =>
+          env.persistenceId == persistenceId && env.sequenceNr >= fromSequenceNr && env.sequenceNr <= toSequenceNr
+        }))
+      else
+        None
+    }
+  }
+
   // test model is as simple as a text that gets other string concatenated to it
   case class ConcatStr(id: String, text: String) {
     def concat(newMsg: String): ConcatStr = {
@@ -326,6 +393,32 @@ class DynamoDBTimestampOffsetProjectionSpec
       enableCurrentEventsByPersistenceId)
   }
 
+  // envelopes are emitted by the "query" source, but allEnvelopes can be loaded
+  def createJavaSourceProviderWithMoreEnvelopes(
+      envelopes: immutable.IndexedSeq[EventEnvelope[String]],
+      allEnvelopes: immutable.IndexedSeq[EventEnvelope[String]],
+      enableCurrentEventsByPersistenceId: Boolean,
+      complete: Boolean = true): JavaTestTimestampSourceProvider = {
+    val sp =
+      akka.projection.testkit.javadsl.TestSourceProvider
+        .create[Offset, EventEnvelope[String]](akka.stream.javadsl.Source.from(envelopes.asJava), _.offset)
+        .withStartSourceFrom {
+          case (lastProcessedOffsetBySlice: TimestampOffsetBySlice, offset: TimestampOffset) =>
+            // FIXME: should have the envelope slice to handle this properly
+            val lastProcessedOffset = lastProcessedOffsetBySlice.offsets.head._2
+            offset.timestamp.isBefore(lastProcessedOffset.timestamp) ||
+            (offset.timestamp == lastProcessedOffset.timestamp && offset.seen == lastProcessedOffset.seen)
+          case _ => false
+        }
+        .withAllowCompletion(complete)
+
+    new JavaTestTimestampSourceProvider(
+      allEnvelopes,
+      sp,
+      persistenceExt.numberOfSlices - 1,
+      enableCurrentEventsByPersistenceId)
+  }
+
   def createBacktrackingSourceProvider(
       envelopes: immutable.IndexedSeq[EventEnvelope[String]],
       complete: Boolean = true): TestTimestampSourceProvider = {
@@ -1884,6 +1977,129 @@ class DynamoDBTimestampOffsetProjectionSpec
         latestOffsetShouldBe(allEnvelopes.last.offset)
       }
     }
+
+    "replay rejected sequence numbers for at-least-once grouped (javadsl)" in {
+      val pid1 = UUID.randomUUID().toString
+      val pid2 = UUID.randomUUID().toString
+      val projectionId = genRandomProjectionId()
+
+      val allEnvelopes = createEnvelopes(pid1, 10) ++ createEnvelopes(pid2, 3)
+      val skipPid1SeqNrs = Set(3L, 4L, 5L, 7L, 9L)
+      val envelopes = allEnvelopes.filterNot { env =>
+        (env.persistenceId == pid1 && skipPid1SeqNrs(env.sequenceNr)) ||
+        (env.persistenceId == pid2 && (env.sequenceNr == 1))
+      }
+
+      val sourceProvider =
+        createJavaSourceProviderWithMoreEnvelopes(envelopes, allEnvelopes, enableCurrentEventsByPersistenceId = true)
+
+      implicit val offsetStore: DynamoDBOffsetStore =
+        new DynamoDBOffsetStore(projectionId, Some(sourceProvider), system, settings, client)
+
+      val results = new ConcurrentHashMap[String, String]()
+
+      val handler: akka.projection.javadsl.Handler[java.util.List[EventEnvelope[String]]] =
+        (envelopes: java.util.List[EventEnvelope[String]]) => {
+          Future {
+            envelopes.asScala.foreach { envelope =>
+              results.putIfAbsent(envelope.persistenceId, "|")
+              results.computeIfPresent(envelope.persistenceId, (_, value) => value + envelope.event + "|")
+            }
+          }.map(_ => Done.getInstance()).asJava
+        }
+
+      val projection =
+        akka.projection.dynamodb.javadsl.DynamoDBProjection
+          .atLeastOnceGroupedWithin(
+            projectionId,
+            Some(settings.withReplayOnRejectedSequenceNumbers(true)).toJava,
+            sourceProvider,
+            handler = () => handler,
+            system)
+          .withGroup(8, 3.seconds.toJava)
+
+      offsetShouldBeEmpty()
+
+      projectionTestKit.run(projection) {
+        results.get(pid1) shouldBe "|e1|e2|e3|e4|e5|e6|e7|e8|e9|e10|"
+        results.get(pid2) shouldBe "|e1|e2|e3|"
+      }
+
+      eventually {
+        latestOffsetShouldBe(allEnvelopes.last.offset)
+      }
+    }
+
+    "replay rejected sequence numbers due to clock skew on event write for at-least-once grouped (javadsl)" in {
+      val pid1 = UUID.randomUUID().toString
+      val pid2 = UUID.randomUUID().toString
+      val projectionId = genRandomProjectionId()
+
+      val start = tick().instant()
+
+      def createEnvelopesFor(
+          pid: Pid,
+          fromSeqNr: Int,
+          toSeqNr: Int,
+          fromTimestamp: Instant): immutable.IndexedSeq[EventEnvelope[String]] = {
+        (fromSeqNr to toSeqNr).map { n =>
+          createEnvelope(pid, n, fromTimestamp.plusSeconds(n - fromSeqNr), s"e$n")
+        }
+      }
+
+      val envelopes1 =
+        createEnvelopesFor(pid1, 1, 2, start) ++
+        createEnvelopesFor(pid1, 3, 4, start.plusSeconds(4)) ++ // gap
+        createEnvelopesFor(pid1, 5, 9, start.plusSeconds(2)) // clock skew, back 2, and then overlapping
+
+      val envelopes2 =
+        createEnvelopesFor(pid2, 1, 3, start.plusSeconds(10)) ++
+        createEnvelopesFor(pid2, 4, 6, start.plusSeconds(1)) ++ // clock skew, back 9
+        createEnvelopesFor(pid2, 7, 9, start.plusSeconds(20)) // and gap
+
+      val allEnvelopes = envelopes1 ++ envelopes2
+
+      val envelopes = allEnvelopes.sortBy(_.timestamp)
+
+      val sourceProvider =
+        createJavaSourceProviderWithMoreEnvelopes(envelopes, allEnvelopes, enableCurrentEventsByPersistenceId = true)
+
+      implicit val offsetStore: DynamoDBOffsetStore =
+        new DynamoDBOffsetStore(projectionId, Some(sourceProvider), system, settings, client)
+
+      val results = new ConcurrentHashMap[String, String]()
+
+      val handler: akka.projection.javadsl.Handler[java.util.List[EventEnvelope[String]]] =
+        (envelopes: java.util.List[EventEnvelope[String]]) => {
+          Future {
+            envelopes.asScala.foreach { envelope =>
+              results.putIfAbsent(envelope.persistenceId, "|")
+              results.computeIfPresent(envelope.persistenceId, (_, value) => value + envelope.event + "|")
+            }
+          }.map(_ => Done.getInstance()).asJava
+        }
+
+      val projection =
+        akka.projection.dynamodb.javadsl.DynamoDBProjection
+          .atLeastOnceGroupedWithin(
+            projectionId,
+            Some(settings.withReplayOnRejectedSequenceNumbers(true)).toJava,
+            sourceProvider,
+            handler = () => handler,
+            system)
+          .withGroup(2, 3.seconds.toJava)
+
+      offsetShouldBeEmpty()
+
+      projectionTestKit.run(projection) {
+        results.get(pid1) shouldBe "|e1|e2|e3|e4|e5|e6|e7|e8|e9|"
+        results.get(pid2) shouldBe "|e1|e2|e3|e4|e5|e6|e7|e8|e9|"
+      }
+
+      eventually {
+        latestOffsetShouldBe(allEnvelopes.last.offset)
+      }
+    }
   }
 
   "A DynamoDB flow projection with TimestampOffset" must {
diff --git a/akka-projection-dynamodb/src/main/scala/akka/projection/dynamodb/internal/DynamoDBProjectionImpl.scala b/akka-projection-dynamodb/src/main/scala/akka/projection/dynamodb/internal/DynamoDBProjectionImpl.scala
index 8c8fef6b4..34a3e679d 100644
--- a/akka-projection-dynamodb/src/main/scala/akka/projection/dynamodb/internal/DynamoDBProjectionImpl.scala
+++ b/akka-projection-dynamodb/src/main/scala/akka/projection/dynamodb/internal/DynamoDBProjectionImpl.scala
@@ -48,6 +48,7 @@ import akka.projection.internal.GroupedHandlerStrategy
 import akka.projection.internal.HandlerStrategy
 import akka.projection.internal.InternalProjection
 import akka.projection.internal.InternalProjectionState
+import akka.projection.internal.JavaToScalaBySliceSourceProviderAdapter
 import akka.projection.internal.ManagementState
 import akka.projection.internal.OffsetStoredByHandler
 import akka.projection.internal.OffsetStrategy
@@ -218,7 +219,11 @@ private[projection] object DynamoDBProjectionImpl {
         val logPrefix = offsetStore.logPrefix
         originalEnvelope match {
           case originalEventEnvelope: EventEnvelope[Any @unchecked] if originalEventEnvelope.sequenceNr > 1 =>
-            sourceProvider match {
+            val underlyingProvider = sourceProvider match {
+              case adapted: JavaToScalaBySliceSourceProviderAdapter[_, _] => adapted.delegate
+              case provider                                               => provider
+            }
+            underlyingProvider match {
               case provider: LoadEventsByPersistenceIdSourceProvider[Any @unchecked]
                   if offsetStore.settings.replayOnRejectedSequenceNumbers =>
                 val persistenceId = originalEventEnvelope.persistenceId
@@ -329,7 +334,11 @@ private[projection] object DynamoDBProjectionImpl {
         val logPrefix = offsetStore.logPrefix
         originalEnvelope match {
           case originalEventEnvelope: EventEnvelope[Any @unchecked] if originalEventEnvelope.sequenceNr > 1 =>
-            sourceProvider match {
+            val underlyingProvider = sourceProvider match {
+              case adapted: JavaToScalaBySliceSourceProviderAdapter[_, _] => adapted.delegate
+              case provider                                               => provider
+            }
+            underlyingProvider match {
               case provider: LoadEventsByPersistenceIdSourceProvider[Any @unchecked]
                   if offsetStore.settings.replayOnRejectedSequenceNumbers =>
                 val persistenceId = originalEventEnvelope.persistenceId
@@ -478,7 +487,11 @@ private[projection] object DynamoDBProjectionImpl {
         val logPrefix = offsetStore.logPrefix
         originalEnvelope match {
           case originalEventEnvelope: EventEnvelope[Any @unchecked] if originalEventEnvelope.sequenceNr > 1 =>
-            sourceProvider match {
+            val underlyingProvider = sourceProvider match {
+              case adapted: JavaToScalaBySliceSourceProviderAdapter[_, _] => adapted.delegate
+              case provider                                               => provider
+            }
+            underlyingProvider match {
               case provider: LoadEventsByPersistenceIdSourceProvider[Any @unchecked]
                   if offsetStore.settings.replayOnRejectedSequenceNumbers =>
                 val persistenceId = originalEventEnvelope.persistenceId
@@ -631,7 +644,11 @@ private[projection] object DynamoDBProjectionImpl {
         val logPrefix = offsetStore.logPrefix
         originalEnvelope match {
           case originalEventEnvelope: EventEnvelope[Any @unchecked] if originalEventEnvelope.sequenceNr > 1 =>
-            sourceProvider match {
+            val underlyingProvider = sourceProvider match {
+              case adapted: JavaToScalaBySliceSourceProviderAdapter[_, _] => adapted.delegate
+              case provider                                               => provider
+            }
+            underlyingProvider match {
               case provider: LoadEventsByPersistenceIdSourceProvider[Any @unchecked]
                   if offsetStore.settings.replayOnRejectedSequenceNumbers =>
                 val persistenceId = originalEventEnvelope.persistenceId
@@ -713,7 +730,11 @@ private[projection] object DynamoDBProjectionImpl {
       val logPrefix = offsetStore.logPrefix
       originalEnvelope match {
         case originalEventEnvelope: EventEnvelope[Any @unchecked] if originalEventEnvelope.sequenceNr > 1 =>
-          sourceProvider match {
+          val underlyingProvider = sourceProvider match {
+            case adapted: JavaToScalaBySliceSourceProviderAdapter[_, _] => adapted.delegate
+            case provider                                               => provider
+          }
+          underlyingProvider match {
             case provider: LoadEventsByPersistenceIdSourceProvider[Any @unchecked]
                 if offsetStore.settings.replayOnRejectedSequenceNumbers =>
               val persistenceId = originalEventEnvelope.persistenceId