Failed to obtain agent card: 502

[mescaja]

I run into this issue while testing various A2A agent scenarios (A2A SDK version used was 0.3.3.Final)

<!-- A2A SDK version - centralized for all agents -->
        <io.a2a.sdk.version>0.3.3.Final</io.a2a.sdk.version>

        <!-- Common dependency versions -->
        <quarkus.platform.version>3.30.1</quarkus.platform.version>

Deployment:

• 1 server A2A agent running locally available on http://localhost:11000
• 1 server A2A agent running in Kubernetes available on http://wanaku-a2a-agent.poc
• 1 java client A2A agent running locally based on
  samples/java/agents/dice_agent_multi_transport/client/src/main/java/com/samples/a2a/client/TestClientRunner.java
• A2A Inspector running locally and available on http://localhost:5001/

The server A2A agent running locally and in Kubernetes is the same.

we're able to pull back the agent card successfully

http://localhost:11000/.well-known/agent-card.json
http://wanaku-a2a-agent.poc/.well-known/agent-card.json

Scenario 1: it does work

java client A2A Agent (running locally) >> A2A Server Agent (running locally on port 11000)

jbang TestClientRunner.java --server-url http://localhost:11000 --message "Convert from EUR to GBP"
Connecting to agent at: http://localhost:11000
Successfully fetched public agent card:
{"name":"Wanaku Agent","description":"Function calling to Wanaku MCP toolbox. it can call currency conversion API to convert currencies it can call external APIs. It can call petstore API to get information.","url":"http://localhost:11000","version":"1.0.0","documentationUrl":"http://example.com/docs","capabilities":{"streaming":true,"pushNotifications":false,"stateTransitionHistory":false},"defaultInputModes":["text"],"defaultOutputModes":["text"],"skills":[{"id":"currency_converter","name":"Currency Converter","description":"Converts currencies using the Wanaku MCP toolbox","tags":["currency","conversion","finance","from","to","amount"],"examples":["Convert 100 USD to EUR","What is 2500 JPY in GBP?"]},{"id":"petstore_info","name":"Petstore Information","description":"Provides information about the petstore","tags":["petstore","information","pets","users","store"],"examples":["get the list of available pets in the petstore","get information about users in the petstore"]}],"supportsAuthenticatedExtendedCard":false,"additionalInterfaces":[{"transport":"HTTP+JSON","url":"http://localhost:11000"},{"transport":"GRPC","url":"http://localhost:11000"}],"preferredTransport":"JSONRPC","protocolVersion":"0.3.0"}
Using public agent card for client initialization.
Sending message: Convert from EUR to GBP
Message sent successfully. Waiting for response...
Received Task status-update: submitted
Received Task status-update: working
Received Task artifact-update: The conversion rate from EUR to GBP is 1 EUR = 0.87726 GBP.
Received Task status-update: completed
Final response: The conversion rate from EUR to GBP is 1 EUR = 0.87726 GBP.

Scenario 2: it does work

A2A Ispector (running locally) >> A2A Server Agent (running locally on port 11000)
Agent Card Url: http://localhost:11000/.well-known/agent-card.json (Agent Card is valid)
send message: convert from GBP to EUR
Response:

{
  "artifact": {
    "artifactId": "d9824b81-b182-4b73-8782-45af34439c1d",
    "parts": [
      {
        "kind": "text",
        "text": "The conversion rate from GBP to EUR is 1.13647."
      }
    ]
  },
  "contextId": "9089e5c1-987e-48e2-aba0-3977cf8dd1ce",
  "kind": "artifact-update",
  "taskId": "9b3bea53-5daf-4b36-89ce-17bbb83b465b",
  "id": "msg-1764764493215-z7408ih2s",
  "validation_errors": []
}

Scenario 3: it does work

A2A Ispector (running locally) >> A2A Server Agent (running in kubernetes on http://wanaku-a2a-agent.poc)
Agent Card Url: http://wanaku-a2a-agent.poc/.well-known/agent-card.json (Agent Card is valid)
send message: convert from GBP to EUR
Response:

{
  "artifact": {
    "artifactId": "7224f787-729c-47d3-93d3-ca741b02548f",
    "parts": [
      {
        "kind": "text",
        "text": "The conversion rate from GBP to EUR is currently 1.13981."
      }
    ]
  },
  "contextId": "67c65f2c-b285-4d06-afa3-046fee0a9ef1",
  "kind": "artifact-update",
  "taskId": "557c90f0-e2a4-485a-8a45-a568725d49f2",
  "id": "msg-1764764626853-ycj5xnv3c",
  "validation_errors": []
}

Scenario 4: it does NOT work

java client A2A Agent (running locally) >> A2A Server Agent (running in kubernetes on http://wanaku-a2a-agent.poc)

jbang TestClientRunner.java --server-url http://wanaku-a2a-agent.poc --message "Convert from EUR to GBP"
Connecting to agent at: http://wanaku-a2a-agent.poc
An error occurred: Failed to obtain agent card: 502
io.a2a.spec.A2AClientError: Failed to obtain agent card: 502
	at io.a2a.client.http.A2ACardResolver.getAgentCard(A2ACardResolver.java:101)
	at com.samples.a2a.client.TestClient.main(TestClient.java:92)
	at TestClientRunner.main(TestClientRunner.java:41)

[mescaja]

the agent card metadata http://localhost:11000/.well-known/agent-card.json

{
  "name": "Wanaku Agent",
  "description": "Function calling to Wanaku MCP toolbox. it can call currency conversion API to convert currencies it can call external APIs. It can call petstore API to get information.",
  "url": "http://localhost:11000",
  "version": "1.0.0",
  "documentationUrl": "http://example.com/docs",
  "capabilities": {
    "streaming": true,
    "pushNotifications": false,
    "stateTransitionHistory": false
  },
  "defaultInputModes": [
    "text"
  ],
  "defaultOutputModes": [
    "text"
  ],
  "skills": [
    {
      "id": "currency_converter",
      "name": "Currency Converter",
      "description": "Converts currencies using the Wanaku MCP toolbox",
      "tags": [
        "currency",
        "conversion",
        "finance",
        "from",
        "to",
        "amount"
      ],
      "examples": [
        "Convert 100 USD to EUR",
        "What is 2500 JPY in GBP?"
      ]
    },
    {
      "id": "petstore_info",
      "name": "Petstore Information",
      "description": "Provides information about the petstore",
      "tags": [
        "petstore",
        "information",
        "pets",
        "users",
        "store"
      ],
      "examples": [
        "get the list of available pets in the petstore",
        "get information about users in the petstore"
      ]
    }
  ],
  "supportsAuthenticatedExtendedCard": false,
  "additionalInterfaces": [
    {
      "transport": "HTTP+JSON",
      "url": "http://localhost:11000"
    },
    {
      "transport": "GRPC",
      "url": "http://localhost:11000"
    }
  ],
  "preferredTransport": "JSONRPC",
  "protocolVersion": "0.3.0"
}

[mescaja]

the other agent card metadata http://wanaku-a2a-agent.poc/.well-known/agent-card.json

{
  "name": "Wanaku Agent",
  "description": "Function calling to Wanaku MCP toolbox. it can call currency conversion API to convert currencies it can call external APIs. It can call petstore API to get information.",
  "url": "http://wanaku-a2a-agent.poc",
  "version": "1.0.0",
  "documentationUrl": "http://example.com/docs",
  "capabilities": {
    "streaming": true,
    "pushNotifications": false,
    "stateTransitionHistory": false
  },
  "defaultInputModes": [
    "text"
  ],
  "defaultOutputModes": [
    "text"
  ],
  "skills": [
    {
      "id": "currency_converter",
      "name": "Currency Converter",
      "description": "Converts currencies using the Wanaku MCP toolbox",
      "tags": [
        "currency",
        "conversion",
        "finance",
        "from",
        "to",
        "amount"
      ],
      "examples": [
        "Convert 100 USD to EUR",
        "What is 2500 JPY in GBP?"
      ]
    },
    {
      "id": "petstore_info",
      "name": "Petstore Information",
      "description": "Provides information about the petstore",
      "tags": [
        "petstore",
        "information",
        "pets",
        "users",
        "store"
      ],
      "examples": [
        "get the list of available pets in the petstore",
        "get information about users in the petstore"
      ]
    }
  ],
  "supportsAuthenticatedExtendedCard": false,
  "additionalInterfaces": [
    {
      "transport": "HTTP+JSON",
      "url": "http://wanaku-a2a-agent.poc"
    },
    {
      "transport": "GRPC",
      "url": "http://wanaku-a2a-agent.poc"
    }
  ],
  "preferredTransport": "JSONRPC",
  "protocolVersion": "0.3.0"
}

[kabir]

Sorry, I am a bit lost. Your latest example seems to be the scenario that was not working? Is the JSON there from actually obtaining the agent card (so it works now) or a dump of what it looks like on the server?

Looking in our code, a 502 can happen in the RestHandler (when HTTP+JSON is used), but in your setup it should use JSONRPC which AFAIK would not throw this error code.

I don't know if this helps, but have you tried this example? https://github.com/a2aproject/a2a-java/tree/main/examples/cloud-deployment

And have you tried with a local Kubernetes instance, assuming that http://wanaku-a2a-agent.poc is something remote?

[mescaja]

yes scenario 4 does not work, the other 3 do work. the same client agent (from scenario 1) is able to fetch the agent card from a local server agent but is not able to when the same server agent is deployed to kubernetes (scenario 4)

Kubernetes exposes the server agent through an ingress (host wanaku-a2a-agent.poc)

Client agent >> Ingress >> Service >> Pod (Server agent inside pod)

[ehsavoie]

Can you try to run the test client with
-Djdk.httpclient.HttpClient.log="errors,requests,headers,frames:control:data:window,ssl,trace,channel"

[mescaja]

Added this to the TestClientRunner.java

System.setProperty("jdk.httpclient.HttpClient.log", "all");

Run this

jbang TestClientRunner.java --server-url http://wanaku-a2a-agent.poc --message "Convert from EUR to GBP"

Response:

[jbang] Building jar for TestClientRunner.java...
Connecting to agent at: http://wanaku-a2a-agent.poc
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.HttpClientImpl$SelectorManager run
INFO: CHANNEL: HttpClient-1-SelectorManager: starting
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying request filters
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying jdk.internal.net.http.AuthenticationFilter@31c88ec8
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying jdk.internal.net.http.RedirectFilter@7ed7259e
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: All filters applied
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription handleSubscribeEvent
INFO: CHANNEL: Start reading from java.nio.channels.SocketChannel[connected local=/192.168.49.1:46446 remote=wanaku-a2a-agent.poc/192.168.49.2:80]
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.Http1Request headers
INFO: REQUEST: http://wanaku-a2a-agent.poc/.well-known/agent-card.json GET
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.Http1AsyncReceiver$Http1TubeSubscriber onSubscribe
INFO: CHANNEL: HTTP/1 read subscriber got subscription from http://wanaku-a2a-agent.poc/.well-known/agent-card.json GET
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber startSubscription
INFO: CHANNEL: Start requesting bytes for writing to channel: java.nio.channels.SocketChannel[connected local=/192.168.49.1:46446 remote=wanaku-a2a-agent.poc/192.168.49.2:80]
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.Http1Request logHeaders
INFO: HEADERS: REQUEST HEADERS:
GET /.well-known/agent-card.json HTTP/1.1
Connection: Upgrade, HTTP2-Settings
Host: wanaku-a2a-agent.poc
HTTP2-Settings: AAEAAEAAAAIAAAAAAAMAAAAAAAQBAAAAAAUAAEAAAAYABgAA
Upgrade: h2c
User-Agent: Java-http-client/24
Content-Type: application/json

Dec 05, 2025 1:30:22 PM jdk.internal.net.http.Http1Response lambda$readHeadersAsync$0
INFO: HEADERS: RESPONSE HEADERS:
    connection: keep-alive
    content-length: 150
    content-type: text/html
    date: Fri, 05 Dec 2025 13:30:22 GMT

Dec 05, 2025 1:30:22 PM jdk.internal.net.http.Exchange lambda$wrapForLog$0
INFO: RESPONSE: (GET http://wanaku-a2a-agent.poc/.well-known/agent-card.json) 502 HTTP_1_1 Local port:  46446
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying response filters
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying jdk.internal.net.http.RedirectFilter@7ed7259e
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying jdk.internal.net.http.AuthenticationFilter@31c88ec8
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: All filters applied
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.Http1Response onFinished
INFO: MISC: Attempting to return connection to the pool: PlainHttpConnection: HttpConnection: java.nio.channels.SocketChannel[connected local=/192.168.49.1:46446 remote=wanaku-a2a-agent.poc/192.168.49.2:80]
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.HttpConnection closeOrReturnToCache
INFO: MISC: Returning connection to the pool: PlainHttpConnection: HttpConnection: java.nio.channels.SocketChannel[connected local=/192.168.49.1:46446 remote=wanaku-a2a-agent.poc/192.168.49.2:80]
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription handleSubscribeEvent
INFO: CHANNEL: Start reading from java.nio.channels.SocketChannel[connected local=/192.168.49.1:46446 remote=wanaku-a2a-agent.poc/192.168.49.2:80]
Dec 05, 2025 1:30:22 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber startSubscription
INFO: CHANNEL: Start requesting bytes for writing to channel: java.nio.channels.SocketChannel[connected local=/192.168.49.1:46446 remote=wanaku-a2a-agent.poc/192.168.49.2:80]
An error occurred: Failed to obtain agent card: 502
io.a2a.spec.A2AClientError: Failed to obtain agent card: 502
	at io.a2a.client.http.A2ACardResolver.getAgentCard(A2ACardResolver.java:101)
	at com.samples.a2a.client.TestClient.main(TestClient.java:96)
	at TestClientRunner.main(TestClientRunner.java:42)

[mescaja]

just wanted to confirm that trying http://wanaku-a2a-agent.poc/.well-known/agent-card.json with any web browser, the Server agent is able to serve the agent card metadata

httpClient in the client agent java class is not able to fetch the same agent card metadata from the same url.

[mescaja]

java --version
java 24 2025-03-18
Java(TM) SE Runtime Environment Oracle GraalVM 24-dev+23.1 (build 24+23-jvmci-b01)
Java HotSpot(TM) 64-Bit Server VM Oracle GraalVM 24-dev+23.1 (build 24+23-jvmci-b01, mixed mode, sharing)

not sure that could be factor i am not using jdk17 or 21

[ehsavoie]

In my opinion there is an issue with the underlying http client. I'm not sure how to address that even if the content-type looks strange to me (content-type: text/html as opposed to application/json.

[mescaja]

now i run this. Similar test but the server agent runs locally on port 11000.

jbang TestClientRunner.java --server-url http://localhost:11000 --message "Convert from EUR to GBP"

Response: the i can see the Content-Type response headers is different

Connecting to agent at: http://localhost:11000
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.HttpClientImpl$SelectorManager run
INFO: CHANNEL: HttpClient-1-SelectorManager: starting
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying request filters
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying jdk.internal.net.http.AuthenticationFilter@31c88ec8
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying jdk.internal.net.http.RedirectFilter@7ed7259e
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: All filters applied
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription handleSubscribeEvent
INFO: CHANNEL: Start reading from java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1AsyncReceiver$Http1TubeSubscriber onSubscribe
INFO: CHANNEL: HTTP/1 read subscriber got subscription from http://localhost:11000/.well-known/agent-card.json GET
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1Request headers
INFO: REQUEST: http://localhost:11000/.well-known/agent-card.json GET
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber startSubscription
INFO: CHANNEL: Start requesting bytes for writing to channel: java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1Request logHeaders
INFO: HEADERS: REQUEST HEADERS:
GET /.well-known/agent-card.json HTTP/1.1
Connection: Upgrade, HTTP2-Settings
Host: localhost:11000
HTTP2-Settings: AAEAAEAAAAIAAAAAAAMAAAAAAAQBAAAAAAUAAEAAAAYABgAA
Upgrade: h2c
User-Agent: Java-http-client/24
Content-Type: application/json

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1Response lambda$readHeadersAsync$0
INFO: HEADERS: RESPONSE HEADERS:
    connection: upgrade
    upgrade: h2c

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection <init>
INFO: MISC: Connection send window size 65,535 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription handleSubscribeEvent
INFO: CHANNEL: Start reading from java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber startSubscription
INFO: CHANNEL: Start requesting bytes for writing to channel: java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: /127.0.0.1:60522: start sending connection preface to localhost/127.0.0.1:11000
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1AsyncReceiver stop
INFO: CHANNEL: HTTP/1 read subscriber stopped for <uri unavailable>
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: FRAME: OUT: SETTINGS: length=36, streamid=0, flags=0  Settings: HEADER_TABLE_SIZE=16384 ENABLE_PUSH=0 MAX_CONCURRENT_STREAMS=0 INITIAL_WINDOW_SIZE=16777216 MAX_FRAME_SIZE=16384 MAX_HEADER_LIST_SIZE=393216 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: PREFACE_BYTES sent
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: Settings Frame sent
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: SETTINGS: length=6, streamid=0, flags=0  Settings: MAX_HEADER_LIST_SIZE=8192 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection encodeFrame
INFO: FRAME: OUT: SETTINGS: length=0, streamid=0, flags=ACK  Settings: 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: CHANNEL: Sending initial connection window update frame: 33,488,897 (33,554,432 - 65,535)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: HEADERS: length=33, streamid=1, flags=END_HEADERS PRIORITY 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection encodeFrame
INFO: FRAME: OUT: WINDOW_UPDATE: length=4, streamid=0, flags=0  WindowUpdate: 33488897
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream$HeadersConsumer onDecoded
INFO: MISC: RECEIVED HEADER (streamid=1): :status: 200
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: finished sending connection preface
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream$HeadersConsumer onDecoded
INFO: MISC: RECEIVED HEADER (streamid=1): content-type: application/json
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream$HeadersConsumer onDecoded
INFO: MISC: RECEIVED HEADER (streamid=1): content-length: 1221
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream incoming
INFO: MISC: handling response (streamid=1)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream handleResponse
INFO: HEADERS: RESPONSE HEADERS:
    :status: 200
    content-length: 1221
    content-type: application/json

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream completeResponse
INFO: MISC: Completing response (streamid=1): jdk.internal.net.http.common.MinimalFuture@7b077fff[Not completed] (id=54)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream getResponseAsync
INFO: MISC: Response future (stream=1) is: jdk.internal.net.http.common.MinimalFuture@7b077fff[Not completed] (id=54)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: DATA: length=1221, streamid=1, flags=END_STREAM 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: SETTINGS: length=0, streamid=0, flags=ACK  Settings: 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Exchange lambda$wrapForLog$0
INFO: RESPONSE: (GET http://localhost:11000/.well-known/agent-card.json) 200 HTTP_2 Local port:  60522
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying response filters
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying jdk.internal.net.http.RedirectFilter@7ed7259e
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying jdk.internal.net.http.AuthenticationFilter@31c88ec8
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: All filters applied
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream readBodyAsync
INFO: MISC: Reading body on stream 1
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream schedule
INFO: MISC: responseSubscriber.onNext 1,221
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream schedule
INFO: MISC: responseSubscriber.onComplete
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream close
INFO: MISC: Closing stream 1
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.HttpClientImpl registerTimer
INFO: MISC: Registering timer IdleConnectionTimeoutEvent, TimeoutEvent[id=1, duration=PT30S, deadline=Deadline(2025-12-05T15:45:55.541844543Z)]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream close
INFO: MISC: Stream 1 closed
Successfully fetched public agent card:
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.HttpClientImpl$SelectorManager run
INFO: MISC: HttpClient-1-SelectorManager: HttpClient finished. Exiting...
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.HttpClientImpl$SelectorManager run
INFO: CHANNEL: HttpClient-1-SelectorManager: stopping
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.HttpClientImpl$SelectorManager shutdown
INFO: MISC: HttpClient-1-SelectorManager: shutting down
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection close
INFO: MISC: Closing HTTP/2 connection: to localhost/127.0.0.1:11000
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection encodeFrame
INFO: FRAME: OUT: GOAWAY: length=25, streamid=0, flags=0  Error: Not an error lastStreamId=0, Debugdata: Requested by user
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber signalError
INFO: CHANNEL: Failed to write to channel (java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]: java.io.IOException: selector manager closed)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher signalError
INFO: CHANNEL: Error signalled on channel java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]: java.io.IOException: selector manager closed
{"name":"Wanaku Agent","description":"Function calling to Wanaku MCP toolbox. it can call currency conversion API to convert currencies it can call external APIs. It can call petstore API to get information.","url":"http://localhost:11000","version":"1.0.0","documentationUrl":"http://example.com/docs","capabilities":{"streaming":true,"pushNotifications":false,"stateTransitionHistory":false},"defaultInputModes":["text"],"defaultOutputModes":["text"],"skills":[{"id":"currency_converter","name":"Currency Converter","description":"Converts currencies using the Wanaku MCP toolbox","tags":["currency","conversion","finance","from","to","amount"],"examples":["Convert 100 USD to EUR","What is 2500 JPY in GBP?"]},{"id":"petstore_info","name":"Petstore Information","description":"Provides information about the petstore","tags":["petstore","information","pets","users","store"],"examples":["get the list of available pets in the petstore","get information about users in the petstore"]}],"supportsAuthenticatedExtendedCard":false,"additionalInterfaces":[{"transport":"HTTP+JSON","url":"http://localhost:11000"},{"transport":"GRPC","url":"http://localhost:11000"}],"preferredTransport":"JSONRPC","protocolVersion":"0.3.0"}
Using public agent card for client initialization.
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription read
INFO: CHANNEL: Raising error with subscriber for java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]: java.io.IOException: selector manager closed
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription read
INFO: CHANNEL: Stopped reading from channel java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection shutdown
INFO: ERROR: java.io.IOException: selector manager closed
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.selectorClosedException(HttpClientImpl.java:1137)
	at java.net.http/jdk.internal.net.http.HttpClientImpl.selectorClosedException(HttpClientImpl.java:907)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalWriteSubscriber.tryFlushCurrent(SocketTube.java:346)
	at java.net.http/jdk.internal.net.http.SocketTube$InternalWriteSubscriber.onNext(SocketTube.java:318)
	at java.net.http/jdk.internal.net.http.SocketTube.onNext(SocketTube.java:136)
	at java.net.http/jdk.internal.net.http.SocketTube.onNext(SocketTube.java:59)
	at java.net.http/jdk.internal.net.http.HttpConnection$PlainHttpPublisher$HttpWriteSubscription.flush(HttpConnection.java:542)
	at java.net.http/jdk.internal.net.http.HttpConnection$PlainHttpPublisher.flushTask(HttpConnection.java:496)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:207)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:280)
	at java.net.http/jdk.internal.net.http.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:233)
	at java.net.http/jdk.internal.net.http.HttpConnection$PlainHttpPublisher.signal(HttpConnection.java:503)
	at java.net.http/jdk.internal.net.http.HttpConnection$PlainHttpPublisher.signalEnqueued(HttpConnection.java:565)
	at java.net.http/jdk.internal.net.http.Http2Connection.sendFrame(Http2Connection.java:1758)
	at java.net.http/jdk.internal.net.http.Http2Connection.close(Http2Connection.java:822)
	at java.net.http/jdk.internal.net.http.Http2ClientImpl.close(Http2ClientImpl.java:256)
	at java.base/java.util.concurrent.ConcurrentHashMap.removeValueIf(ConcurrentHashMap.java:1665)
	at java.base/java.util.concurrent.ConcurrentHashMap$ValuesView.removeIf(ConcurrentHashMap.java:4772)
	at java.net.http/jdk.internal.net.http.Http2ClientImpl.stop(Http2ClientImpl.java:248)
	at java.net.http/jdk.internal.net.http.HttpClientImpl.stop(HttpClientImpl.java:545)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.shutdown(HttpClientImpl.java:1250)
	at java.net.http/jdk.internal.net.http.HttpClientImpl$SelectorManager.run(HttpClientImpl.java:1452)

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.PlainHttpConnection close
INFO: MISC: Closing: PlainHttpConnection: HttpConnection: java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.PlainHttpConnection close
INFO: CHANNEL: Closing channel: java.nio.channels.SocketChannel[connected local=/127.0.0.1:60522 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube signalClosed
INFO: CHANNEL: Connection close signalled: connection closed locally (java.nio.channels.SocketChannel[closed])
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber$WriteSubscription cancel
INFO: CHANNEL: Cancelling write subscription
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.HttpClientImpl$SelectorManager run
INFO: CHANNEL: HttpClient-2-SelectorManager: starting
Sending message: Convert from EUR to GBP
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying request filters
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying jdk.internal.net.http.AuthenticationFilter@333e0630
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: Applying jdk.internal.net.http.RedirectFilter@39c66d40
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange requestFilters
INFO: MISC: All filters applied
Message sent successfully. Waiting for response...
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription handleSubscribeEvent
INFO: CHANNEL: Start reading from java.nio.channels.SocketChannel[connected local=/127.0.0.1:60534 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1AsyncReceiver$Http1TubeSubscriber onSubscribe
INFO: CHANNEL: HTTP/1 read subscriber got subscription from http://localhost:11000 POST
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1Request headers
INFO: REQUEST: http://localhost:11000 POST
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1Request logHeaders
INFO: HEADERS: REQUEST HEADERS:
POST / HTTP/1.1
Connection: Upgrade, HTTP2-Settings
Content-Length: 330
Host: localhost:11000
HTTP2-Settings: AAEAAEAAAAIAAAAAAAMAAAAAAAQBAAAAAAUAAEAAAAYABgAA
Upgrade: h2c
User-Agent: Java-http-client/24
Accept: text/event-stream
Content-Type: application/json

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber startSubscription
INFO: CHANNEL: Start requesting bytes for writing to channel: java.nio.channels.SocketChannel[connected local=/127.0.0.1:60534 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1Response lambda$readHeadersAsync$0
INFO: HEADERS: RESPONSE HEADERS:
    connection: upgrade
    upgrade: h2c

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection <init>
INFO: MISC: Connection send window size 65,535 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalReadPublisher$InternalReadSubscription handleSubscribeEvent
INFO: CHANNEL: Start reading from java.nio.channels.SocketChannel[connected local=/127.0.0.1:60534 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http1AsyncReceiver stop
INFO: CHANNEL: HTTP/1 read subscriber stopped for <uri unavailable>
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.SocketTube$InternalWriteSubscriber startSubscription
INFO: CHANNEL: Start requesting bytes for writing to channel: java.nio.channels.SocketChannel[connected local=/127.0.0.1:60534 remote=localhost/127.0.0.1:11000]
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: /127.0.0.1:60534: start sending connection preface to localhost/127.0.0.1:11000
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: FRAME: OUT: SETTINGS: length=36, streamid=0, flags=0  Settings: HEADER_TABLE_SIZE=16384 ENABLE_PUSH=0 MAX_CONCURRENT_STREAMS=0 INITIAL_WINDOW_SIZE=16777216 MAX_FRAME_SIZE=16384 MAX_HEADER_LIST_SIZE=393216 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: PREFACE_BYTES sent
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: SETTINGS: length=6, streamid=0, flags=0  Settings: MAX_HEADER_LIST_SIZE=8192 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection encodeFrame
INFO: FRAME: OUT: SETTINGS: length=0, streamid=0, flags=ACK  Settings: 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: HEADERS: length=28, streamid=1, flags=END_HEADERS PRIORITY 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream$HeadersConsumer onDecoded
INFO: MISC: RECEIVED HEADER (streamid=1): :status: 200
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream$HeadersConsumer onDecoded
INFO: MISC: RECEIVED HEADER (streamid=1): content-type: text/event-stream
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream incoming
INFO: MISC: handling response (streamid=1)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream handleResponse
INFO: HEADERS: RESPONSE HEADERS:
    :status: 200
    content-type: text/event-stream

Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream completeResponse
INFO: MISC: Created completed future (streamid=1): jdk.internal.net.http.common.MinimalFuture@7cc4f41c[Completed normally] (id=123)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: DATA: length=298, streamid=1, flags=0 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: DATA: length=296, streamid=1, flags=0 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: SETTINGS: length=0, streamid=0, flags=ACK  Settings: 
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: Settings Frame sent
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: CHANNEL: Sending initial connection window update frame: 33,488,897 (33,554,432 - 65,535)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection encodeFrame
INFO: FRAME: OUT: WINDOW_UPDATE: length=4, streamid=0, flags=0  WindowUpdate: 33488897
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Http2Connection sendConnectionPreface
INFO: MISC: finished sending connection preface
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream getResponseAsync
INFO: MISC: Response future (stream=1) is: jdk.internal.net.http.common.MinimalFuture@7cc4f41c[Completed normally] (id=123)
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Exchange lambda$wrapForLog$0
INFO: RESPONSE: (POST http://localhost:11000) 200 HTTP_2 Local port:  60534
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying response filters
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying jdk.internal.net.http.RedirectFilter@39c66d40
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: Applying jdk.internal.net.http.AuthenticationFilter@333e0630
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.MultiExchange responseFilters
INFO: MISC: All filters applied
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream readBodyAsync
INFO: MISC: Reading body on stream 1
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream schedule
INFO: MISC: responseSubscriber.onNext 298
Received Task status-update: submitted
Dec 05, 2025 3:45:25 PM jdk.internal.net.http.Stream schedule
INFO: MISC: responseSubscriber.onNext 296
Received Task status-update: working
Dec 05, 2025 3:45:26 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: DATA: length=370, streamid=1, flags=0 
Dec 05, 2025 3:45:26 PM jdk.internal.net.http.Stream schedule
INFO: MISC: responseSubscriber.onNext 370
Received Task artifact-update: The conversion rate from EUR to GBP is 1 EUR = 0.87272 GBP.
Dec 05, 2025 3:45:26 PM jdk.internal.net.http.Http2Connection processFrame
INFO: FRAME: IN: DATA: length=297, streamid=1, flags=0 
Dec 05, 2025 3:45:26 PM jdk.internal.net.http.Stream schedule
INFO: MISC: responseSubscriber.onNext 297
Received Task status-update: completed
Final response: The conversion rate from EUR to GBP is 1 EUR = 0.87272 GBP.

[mescaja]

the strange thing is that if i run a test from A2A Inspector with agent card url http://wanaku-a2a-agent.poc, it does work.

A2A Agent Inspector app is written in Python where the TestClientRunner.java is not. I think that makes me thinking that ths issue is in the java client agent class

[ehsavoie]

I'm wondering if it is somewhat similar to #270
Could you try on a different JDK version ?

[mescaja]

Install 2 Oracle JDK, 17 and 21

sdk i java 17.0.12-oracle
sdk i java 21.0.9-oracle

with JDK-17

sdk use java 17.0.12-oracle
java --version
java 17.0.12 2024-07-16 LTS
Java(TM) SE Runtime Environment (build 17.0.12+8-LTS-286)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.12+8-LTS-286, mixed mode, sharing)

jbang TestClientRunner.java --server-url http://localhost:11000 --message "Convert from EUR to GBP" ----- Ok
jbang TestClientRunner.java --server-url http://wanaku-a2a-agent.poc --message "Convert from EUR to GBP" ---- same issue

with JDK-21

sdk use java 21.0.9-oracle
java --version
java 21.0.9 2025-10-21 LTS
Java(TM) SE Runtime Environment (build 21.0.9+7-LTS-338)
Java HotSpot(TM) 64-Bit Server VM (build 21.0.9+7-LTS-338, mixed mode, sharing)

jbang TestClientRunner.java --server-url http://localhost:11000 --message "Convert from EUR to GBP" ----- Ok
jbang TestClientRunner.java --server-url http://wanaku-a2a-agent.poc --message "Convert from EUR to GBP" ---- same issue

could not see the JDK switching made any difference. it could be configuration but i don't know what parameters we can tweak to setup the HttpClient

[ehsavoie]

Is your k8s configuration a "real" cluster or a local one like kind or minikube ? Would it be possible to get your configuration to try to recreate