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https://issues.apache.org/jira/browse/ARTEMIS-4327?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Justin Bertram reassigned ARTEMIS-4327:
---------------------------------------

    Assignee:     (was: Clebert Suconic)

>  AMQBuffer.readNullableString() is returning null when the buffer is not empty
> ------------------------------------------------------------------------------
>
>                 Key: ARTEMIS-4327
>                 URL: https://issues.apache.org/jira/browse/ARTEMIS-4327
>             Project: ActiveMQ Artemis
>          Issue Type: Bug
>    Affects Versions: 2.19.1
>         Environment: Artemis client is 
> org.apache.activemq:artemis-core-client:2.19.1, Java code is using the 
> Artemis Core API.
> Artemis server appears to be 2.28.0, and is running in a Docker container.
>            Reporter: Chelsea Salyards
>            Priority: Major
>
> *The Issue*
> Either I do not understand the intended functionality of 
> AMQBuffer.readNullableString(), or it is not functioning correctly. Based on 
> the name, I assumed that it would return null if the buffer was empty, and if 
> it was not, it would return a string.
> In my client code, I have the following:
>  
> ServerLocator locator = ActiveMQClient.createServerLocator(AMQ_BROKER_URL);
> ClientSessionFactory sessionFactory = locator.createSessionFactory();
> ClientSession session = sessionFactory.createSession();
> session.start();
> Client message = session.createMessage(true);
> message.getBodyBuffer().writeString("test string");
> logger.debug("Regular string: " + message.getDataBuffer().readString());
> logger.debug("Nullable string: " + 
> message.getDataBuffer().readNullableString());
> ClientProducer producer = session.createProducer("test-queue");
> producer.send(message);
>  
> The first debug output, using readString() prints out the string "test 
> string" like I expect.
>  
> However, the second debug output prints null, but I expected it to print 
> "test string".
>  
> *Potential Cause*
> I took a look at the message in the queue via the Artemis web console, and I 
> can see the bytes for the message body are as follows:
>  
> 00 00 00 0b 00 0b 74 65 73 74 20 73 74 72 69 6e 67
>  
> Looking at the Artemis client source code, particularly the code for 
> ChannelBufferWrapper, an implementation of the ActiveMQBuffer class, I see 
> that readNullableString() is defined as the following:
>  
> activemq-artemis/artemis-commons/src/main/java/org/apache/activemq/artemis/core/buffers/impl/ChannelBufferWrapper.java
>    public String readNullableString() {
>       int b = buffer.readByte();
>       if (b == DataConstants.NULL) {
>          return null;
>     }
>       return readStringInternal();
>    }
>  
> So if I am reading this correctly, this seems to be saying that if the buffer 
> starts with the byte 00, it will return null, even if the buffer is not 
> empty. Am I reading this correctly? As shown in my example above, the message 
> body starts with byte 00.
> Other details about the message, if it helps:
> durable: true
> protocol: CORE
> type: default



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