# \#java **URL:** https://discuss.akka.io/tag/java/6.md [Latest](https://discuss.akka.io/latest.md) · [Categories](https://discuss.akka.io/categories.md) · [Tags](https://discuss.akka.io/tags.md) --- ## [OpenTelemetry Setup for the new Akka Java SDK](https://discuss.akka.io/t/opentelemetry-setup-for-the-new-akka-java-sdk/11663)
**Author:** [@theleoborges](https://discuss.akka.io/u/theleoborges)\ **Replies:** 9\ **Last updated:** [August 26, 2025, 9:31am UTC](https://discuss.akka.io/t/opentelemetry-setup-for-the-new-akka-java-sdk/11663 "2025-08-26T09:31:26Z")
As per the docs, here’s how I setup my SDK: akka.javasdk { agent { model-provider = openai openai { model-name = "gpt-4o-mini" api-key = ${?OPENAI\_API\_KEY} } } telemetry { tracing { … --- ## [Using implicit Ftps](https://discuss.akka.io/t/using-implicit-ftps/10591)
**Author:** [@sigurd](https://discuss.akka.io/u/sigurd)\ **Replies:** 3\ **Last updated:** [July 10, 2025, 10:50pm UTC](https://discuss.akka.io/t/using-implicit-ftps/10591 "2025-07-10T22:50:57Z")
Hey guys, I’m trying to use implicit FTPS. In the documentation, there is written Use it to configure any custom parameters the server may require, such as explicit or implicit data transfer encryption. FTP • Alpakk… --- ## [My Bug while Using Multiple Cluster sharding with Akka Persistence](https://discuss.akka.io/t/my-bug-while-using-multiple-cluster-sharding-with-akka-persistence/7439)
**Author:** [@mockbean](https://discuss.akka.io/u/mockbean)\ **Replies:** 0\ **Last updated:** [November 5, 2020, 8:52pm UTC](https://discuss.akka.io/t/my-bug-while-using-multiple-cluster-sharding-with-akka-persistence/7439 "2020-11-05T20:52:04Z")
Hello, dear Akka gurus. I’m dealing with a bad bug that I hesitate if it is in my code or not. Consider I have three types of Entities (Actors :slight\_smile:). Type A: Akka’s Default ClusterSharding Type B & C: Kafka… --- ## [Akka cluster tls tcp configuration](https://discuss.akka.io/t/akka-cluster-tls-tcp-configuration/10874)
**Author:** [@jlam](https://discuss.akka.io/u/jlam)\ **Replies:** 0\ **Last updated:** [August 21, 2024, 12:58pm UTC](https://discuss.akka.io/t/akka-cluster-tls-tcp-configuration/10874 "2024-08-21T12:58:09Z")
Hi, I am trying to set a cluster with tls tcp transport with no success.(the nodes in the cluster communicate succesfully with tcp transport(I am new to the X509 certificates) I found the following link: Generating X.5… --- ## [Entity existence on two nodes after rebalance](https://discuss.akka.io/t/entity-existence-on-two-nodes-after-rebalance/10655)
**Author:** [@whizyrel](https://discuss.akka.io/u/whizyrel)\ **Replies:** 1\ **Last updated:** [March 5, 2024, 7:35pm UTC](https://discuss.akka.io/t/entity-existence-on-two-nodes-after-rebalance/10655 "2024-03-05T19:35:09Z")
Akka entity exists on two nodes when node comes back up after rebalance. Well, so far, I am using akka persistence event sourcing, remember entities, timeout cancelled from the actor context, akka-persistence-jdbc plugi… --- ## [Unable to properly terminate the alpakka Kafka Plain source(autocommit) in GraphDSL Stream](https://discuss.akka.io/t/unable-to-properly-terminate-the-alpakka-kafka-plain-source-autocommit-in-graphdsl-stream/10805)
**Author:** [@shanmukh](https://discuss.akka.io/u/shanmukh)\ **Replies:** 0\ **Last updated:** [July 7, 2024, 6:39am UTC](https://discuss.akka.io/t/unable-to-properly-terminate-the-alpakka-kafka-plain-source-autocommit-in-graphdsl-stream/10805 "2024-07-07T06:39:25Z")
I have written a GraphDsl Java stream which uses an Alpakka plain source with auto-commit. The aim is to add functionality to shutdown the source and stream gracefully without loosing the consumed records Problem: Whi… --- ## [Errors using Jackson serialization with durable state store](https://discuss.akka.io/t/errors-using-jackson-serialization-with-durable-state-store/10744)
**Author:** [@swheeler](https://discuss.akka.io/u/swheeler)\ **Replies:** 6\ **Last updated:** [June 5, 2024, 6:40pm UTC](https://discuss.akka.io/t/errors-using-jackson-serialization-with-durable-state-store/10744 "2024-06-05T18:40:56Z")
I am working on switching my application from Java serialization to Jackson. I am running up against an error in my custom durable state store plugin that I am having trouble tracking down. Here is the relevant portion … --- ## [Akka actor Receivers stopped processing of sent messages](https://discuss.akka.io/t/akka-actor-receivers-stopped-processing-of-sent-messages/10697)
**Author:** [@arunkumar1416](https://discuss.akka.io/u/arunkumar1416)\ **Replies:** 6\ **Last updated:** [April 14, 2024, 6:42pm UTC](https://discuss.akka.io/t/akka-actor-receivers-stopped-processing-of-sent-messages/10697 "2024-04-14T18:42:39Z")
In our Java Spring application, we are using Akka messaging library to send and receive the messages. In Message we are passing the object to be process. This sending of objects to receivers happens frequently at every… --- ## [How to reliably send a message from outside the ActorSystem](https://discuss.akka.io/t/how-to-reliably-send-a-message-from-outside-the-actorsystem/10570)
**Author:** [@yarrichar](https://discuss.akka.io/u/yarrichar)\ **Replies:** 3\ **Last updated:** [December 7, 2023, 11:19am UTC](https://discuss.akka.io/t/how-to-reliably-send-a-message-from-outside-the-actorsystem/10570 "2023-12-07T11:19:46Z")
I am wondering how to send a message to an actor from outside the actor system reliably? With actor to actor messages I can set a replyTo/sender field in the message, and use the absence of a reply to work out that I ne… --- ## [system/cluster/core/daemon/joinSeedNodeProcess doesn't match an active actor](https://discuss.akka.io/t/system-cluster-core-daemon-joinseednodeprocess-doesnt-match-an-active-actor/10519)
**Author:** [@javierpajaro](https://discuss.akka.io/u/javierpajaro)\ **Replies:** 2\ **Last updated:** [October 25, 2023, 2:46pm UTC](https://discuss.akka.io/t/system-cluster-core-daemon-joinseednodeprocess-doesnt-match-an-active-actor/10519 "2023-10-25T14:46:45Z")
After (an apparently) succesfull startup, I see DEBUG messages related to joinSeedNodeProcess and firstSeedNodeProcess telling that both actors probably have been stoped. I would like to know if this is and error, and i… --- ## [In Singleton Actor, Scheduler schedule method not running after 1 or 2 runs](https://discuss.akka.io/t/in-singleton-actor-scheduler-schedule-method-not-running-after-1-or-2-runs/10333)
**Author:** [@TheGameDefault](https://discuss.akka.io/u/TheGameDefault)\ **Replies:** 21\ **Last updated:** [September 20, 2023, 6:28pm UTC](https://discuss.akka.io/t/in-singleton-actor-scheduler-schedule-method-not-running-after-1-or-2-runs/10333 "2023-09-20T18:28:50Z")
Akka version is 2.5.23 From Singleton Actor we are calling schedule method to send a self message in every 1 hour. getContext().getSystem().scheduler().schedule(initialDelay, interval, self(), CronActivity.WAKEUP, … --- ## [Can't receive the message in Akka Cluster](https://discuss.akka.io/t/cant-receive-the-message-in-akka-cluster/10442)
**Author:** [@BashirMan8](https://discuss.akka.io/u/BashirMan8)\ **Replies:** 2\ **Last updated:** [August 21, 2023, 10:36am UTC](https://discuss.akka.io/t/cant-receive-the-message-in-akka-cluster/10442 "2023-08-21T10:36:32Z")
Hello everyone, I’m attempting to send a message from senderActor within Microservice A using the concept of “Classic Distributed Publish Subscribe in Cluster” I’m trying to publish the message to the content-topic, but… --- ## [Testkit for DurableState](https://discuss.akka.io/t/testkit-for-durablestate/10425)
**Author:** [@Nilendra](https://discuss.akka.io/u/Nilendra)\ **Replies:** 5\ **Last updated:** [August 14, 2023, 6:51am UTC](https://discuss.akka.io/t/testkit-for-durablestate/10425 "2023-08-14T06:51:53Z")
Hello, I am using DurableState for my project. Earlier I was using EventSourcedBehavior. But after moving to DurableState all my JUnits are failing. I am using PersistenceTestKit and Plugin. We are also using Sharding. … --- ## [Sharding Does Not Processing Message](https://discuss.akka.io/t/sharding-does-not-processing-message/10390)
**Author:** [@gauravappa](https://discuss.akka.io/u/gauravappa)\ **Replies:** 0\ **Last updated:** [July 9, 2023, 4:24pm UTC](https://discuss.akka.io/t/sharding-does-not-processing-message/10390 "2023-07-09T16:24:43Z")
i have send message to sharding envelop but message does not get processed, I have created two node in cluster sharding with configuration as below, akka { loglevel = DEBUG actor { provider = "cluster" serial… --- ## [AKKA library in android studio Koltin project](https://discuss.akka.io/t/akka-library-in-android-studio-koltin-project/10255)
**Author:** [@vazand](https://discuss.akka.io/u/vazand)\ **Replies:** 4\ **Last updated:** [June 3, 2023, 4:01am UTC](https://discuss.akka.io/t/akka-library-in-android-studio-koltin-project/10255 "2023-06-03T04:01:37Z")
Hello friends, I am new to AKKA, and I want some examples of how to use the Akka library in the android studio project. I just want to use the AKKA library instead of Retrofit. is it possible? please share your knowledg… --- ## [Cluster-sharding message did not deserialize correctly](https://discuss.akka.io/t/cluster-sharding-message-did-not-deserialize-correctly/10323)
**Author:** [@fire8862005](https://discuss.akka.io/u/fire8862005)\ **Replies:** 0\ **Last updated:** [May 24, 2023, 4:19am UTC](https://discuss.akka.io/t/cluster-sharding-message-did-not-deserialize-correctly/10323 "2023-05-24T04:19:13Z")
like the topic above ,I received message like this “Failed to deserialize message from \[akka://xxx\] with serializer id \[25\] and manifest \[a\].” my application.conf is like this : “allow-java-serialization = off”, “seri… --- ## [Default value of number-of-shards](https://discuss.akka.io/t/default-value-of-number-of-shards/10307)
**Author:** [@TheGameDefault](https://discuss.akka.io/u/TheGameDefault)\ **Replies:** 6\ **Last updated:** [May 14, 2023, 12:53pm UTC](https://discuss.akka.io/t/default-value-of-number-of-shards/10307 "2023-05-14T12:53:09Z")
Not able to find default value of number-of-shards anywhere. akka.cluster.sharding { # Number of shards used by the default HashCodeMessageExtractor # when no other message extractor is defined. This value must be … --- ## [Am I right: No public \*sources.jar with akka java sources code is publicly available?](https://discuss.akka.io/t/am-i-right-no-public-sources-jar-with-akka-java-sources-code-is-publicly-available/10298)
**Author:** [@ChristianKoelle](https://discuss.akka.io/u/ChristianKoelle)\ **Replies:** 2\ **Last updated:** [May 10, 2023, 1:49pm UTC](https://discuss.akka.io/t/am-i-right-no-public-sources-jar-with-akka-java-sources-code-is-publicly-available/10298 "2023-05-10T13:49:11Z")
Usually, when I drill into external java libraries or frameworks, the java source-code is publicly distributed via \*source.jar files published next to the libraries, typically in a maven-repo. The Java-IDE usually has a … --- ## [How to bubble up the exception root cause in a recursive algorithm (SupervisorStrategy.stop())?](https://discuss.akka.io/t/how-to-bubble-up-the-exception-root-cause-in-a-recursive-algorithm-supervisorstrategy-stop/10297)
**Author:** [@ChristianKoelle](https://discuss.akka.io/u/ChristianKoelle)\ **Replies:** 0\ **Last updated:** [May 2, 2023, 3:37pm UTC](https://discuss.akka.io/t/how-to-bubble-up-the-exception-root-cause-in-a-recursive-algorithm-supervisorstrategy-stop/10297 "2023-05-02T15:37:48Z")
I am keen on getting to know akka, and thanks to every creator of akka involved. I started with a recursive zipping job, i.e. anonymous agents (Behaviours) are spawned with the intention to do the nested work until ever… --- ## [Creating Guardian Actor with SpawnProtocol](https://discuss.akka.io/t/creating-guardian-actor-with-spawnprotocol/9211)
**Author:** [@AND2797](https://discuss.akka.io/u/AND2797)\ **Replies:** 4\ **Last updated:** [May 1, 2023, 7:07am UTC](https://discuss.akka.io/t/creating-guardian-actor-with-spawnprotocol/9211 "2023-05-01T07:07:10Z")
I want to create a GuardianActor with the capability of spawning actors. I’m confused how this actor should be created. Currently I’m trying to do something like this → public class GuardianActor extends AbstractBehavi… --- ## [How to remove/clean-up state of EventSourcedBehavior when task done?](https://discuss.akka.io/t/how-to-remove-clean-up-state-of-eventsourcedbehavior-when-task-done/6363)
**Author:** [@pvoss](https://discuss.akka.io/u/pvoss)\ **Replies:** 9\ **Last updated:** [April 9, 2023, 10:44am UTC](https://discuss.akka.io/t/how-to-remove-clean-up-state-of-eventsourcedbehavior-when-task-done/6363 "2023-04-09T10:44:59Z")
I have some persistent actors (implementing EventSourcedBehavior) that manage certain jobs/tasks. When a job is completed the EventSourceBehavior that was managing it can be stopped and its state (events/snapshot) is not… --- ## [About Akka gRPC](https://discuss.akka.io/t/about-akka-grpc/10218)
**Author:** [@watimuma](https://discuss.akka.io/u/watimuma)\ **Replies:** 6\ **Last updated:** [March 15, 2023, 8:19am UTC](https://discuss.akka.io/t/about-akka-grpc/10218 "2023-03-15T08:19:04Z")
Hi~ I’m trying to use Akka-gRPC .First , I flow the guide Server . My development environment: JDK 11.0.16 Maven configuration: \ \1.8\ \ **Author:** [@aliakbar](https://discuss.akka.io/u/aliakbar)\ **Replies:** 0\ **Last updated:** [February 7, 2023, 10:58am UTC](https://discuss.akka.io/t/java-mission-control-shows-nosuchmethoderror/10168 "2023-02-07T10:58:40Z") We have a large-scale AKKA application in production that serves millions of users every day. Java Flight Recorder reports NoSuchMethodError thrown while running our application on production; I would like to know how to… --- ## [Akka work pull multiple producers support](https://discuss.akka.io/t/akka-work-pull-multiple-producers-support/10139)
**Author:** [@nandhuhareendran93](https://discuss.akka.io/u/nandhuhareendran93)\ **Replies:** 2\ **Last updated:** [January 19, 2023, 9:19am UTC](https://discuss.akka.io/t/akka-work-pull-multiple-producers-support/10139 "2023-01-19T09:19:05Z")
I am trying to explore work pull feature in the Akka cluster. Does the work pull feature supports registering multiple producers to the same service key? I tried the same by referring to the java example provided in the … --- ## [How To get Access to Context in EventSourcedBehavior](https://discuss.akka.io/t/how-to-get-access-to-context-in-eventsourcedbehavior/10141)
**Author:** [@gauravappa](https://discuss.akka.io/u/gauravappa)\ **Replies:** 1\ **Last updated:** [January 19, 2023, 7:37am UTC](https://discuss.akka.io/t/how-to-get-access-to-context-in-eventsourcedbehavior/10141 "2023-01-19T07:37:51Z")
I want to access context in eventSourcedBehaviour to start timers from the EventSourced Actor but now able to find way to wire context in EventSourced Actor --- ## [Using TCP with AKKA Typed](https://discuss.akka.io/t/using-tcp-with-akka-typed/10133)
**Author:** [@haha](https://discuss.akka.io/u/haha)\ **Replies:** 2\ **Last updated:** [January 18, 2023, 11:12am UTC](https://discuss.akka.io/t/using-tcp-with-akka-typed/10133 "2023-01-18T11:12:53Z")
Hi I’m trying to create a TCP server with AKKA typed. I already got a POC working with AKKA Classic based actors, but I’m struggling with converting the full POC to AKKA typed. The current roadblock is that AKKA typed … --- ## [Akka Timers in Cluster Sharding](https://discuss.akka.io/t/akka-timers-in-cluster-sharding/10135)
**Author:** [@gauravappa](https://discuss.akka.io/u/gauravappa)\ **Replies:** 1\ **Last updated:** [January 18, 2023, 11:01am UTC](https://discuss.akka.io/t/akka-timers-in-cluster-sharding/10135 "2023-01-18T11:01:48Z")
I am trying to run timer actor in akka cluster sharding but when one node going down which contains the schedular timer… it is not getting replicated to new shard …the actor is getting replilcated to new shard but ti… --- ## [On the positive impacts of Project Loom and Akka](https://discuss.akka.io/t/on-the-positive-impacts-of-project-loom-and-akka/8123)
**Author:** [@huntc](https://discuss.akka.io/u/huntc)\ **Replies:** 14\ **Last updated:** [November 7, 2022, 5:29pm UTC](https://discuss.akka.io/t/on-the-positive-impacts-of-project-loom-and-akka/8123 "2022-11-07T17:29:14Z")
I’m curious as to the thinking of how the forthcoming Project Loom may positively impact Akka, and in particular, its actors and the way they are developed. In short, Project Loom encourages the use of blocking code bec… --- ## [The shutdown of one node in the cluster results in the shutdown of the other node](https://discuss.akka.io/t/the-shutdown-of-one-node-in-the-cluster-results-in-the-shutdown-of-the-other-node/10059)
**Author:** [@watimuma](https://discuss.akka.io/u/watimuma)\ **Replies:** 2\ **Last updated:** [November 4, 2022, 1:39am UTC](https://discuss.akka.io/t/the-shutdown-of-one-node-in-the-cluster-results-in-the-shutdown-of-the-other-node/10059 "2022-11-04T01:39:35Z")
Hi, I test Shard rebalancing in akka cluster sharding , the specific operations are as follow: Config: akka.cluster { seed-nodes = \[ "akka://cxcount@127.0.0.1:2553", "akka://cxcount@12… --- ## [Why akka tell message is much slower than Java TheadPoolExcutor submit？](https://discuss.akka.io/t/why-akka-tell-message-is-much-slower-than-java-theadpoolexcutor-submit/10066)
**Author:** [@ye](https://discuss.akka.io/u/ye)\ **Replies:** 1\ **Last updated:** [November 3, 2022, 10:51am UTC](https://discuss.akka.io/t/why-akka-tell-message-is-much-slower-than-java-theadpoolexcutor-submit/10066 "2022-11-03T10:51:22Z")
Our company’s engine is built with akka and we are doing performance stress testing. We found that akka tell message is very slow，100 message use about 5-6ns. The result confused us，so we do a test （1）send 100 message… [Next page](https://discuss.akka.io/tag/java/6.md?match_all_tags=true&page=1&tags%5B%5D=java)