[CAMEL-14616] AttachmentConverter is not automatically discovered

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Workaround
• Affects Version/s: 3.0.0, 3.0.1, 3.1.0
• Component/s: camel-mail
• Labels: type-converter

Environment

Reproduced on Windows 7 and CentOS 6.10, with Oracle JDK 8, OpenJDK 8 and OpenJDK 11.

• Estimated Complexity: Unknown
• Assignee: Unassigned
• Reporter: Laurent Chabot
• Created: 25/Feb/20 15:48
• Updated: 25/Feb/20 18:12
• Resolved: 25/Feb/20 18:12

Description

I have a very basic usage of camel-mail that's been working fine with Camel 2.x:

import java.io.IOException;
import org.apache.camel.CamelContext;
import org.apache.camel.ProducerTemplate;
import org.apache.camel.impl.DefaultCamelContext;

public class MailTest {
    public static void main(String[] args) throws IOException {
        try (CamelContext ctx = new DefaultCamelContext(); ProducerTemplate pt = ctx.createProducerTemplate()) {
            ctx.start();
            pt.sendBody("smtp://localhost:25?to=me@mydomain", "Hello, World");
        }
    }
}

It is packaged as an executable jar using maven-assembly-plugin jar-with-dependencies.

When I run it with Camel 3.x (tested with 3.0.0, 3.0.1 and 3.1.0), I get below error:

Exception in thread "main" org.apache.camel.CamelExecutionException: Exception occurred during execution on the exchange: Exchange[]
        at org.apache.camel.CamelExecutionException.wrapCamelExecutionException(CamelExecutionException.java:47)
        at org.apache.camel.support.ExchangeHelper.extractResultBody(ExchangeHelper.java:636)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.extractResultBody(DefaultProducerTemplate.java:568)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.extractResultBody(DefaultProducerTemplate.java:564)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.sendBody(DefaultProducerTemplate.java:189)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.sendBody(DefaultProducerTemplate.java:195)
        at MailTest.main(MailTest.java:10)
Caused by: java.lang.NullPointerException
        at org.apache.camel.component.mail.MailBinding.populateMailMessage(MailBinding.java:133)
        at org.apache.camel.component.mail.MailProducer.process(MailProducer.java:61)
        at org.apache.camel.support.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:67)
        at org.apache.camel.processor.SharedCamelInternalProcessor.process(SharedCamelInternalProcessor.java:212)
        at org.apache.camel.processor.SharedCamelInternalProcessor$1.process(SharedCamelInternalProcessor.java:110)
        at org.apache.camel.impl.engine.DefaultAsyncProcessorAwaitManager.process(DefaultAsyncProcessorAwaitManager.java:84)
        at org.apache.camel.processor.SharedCamelInternalProcessor.process(SharedCamelInternalProcessor.java:107)
        at org.apache.camel.impl.engine.DefaultProducerCache.send(DefaultProducerCache.java:185)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.send(DefaultProducerTemplate.java:176)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.send(DefaultProducerTemplate.java:172)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.send(DefaultProducerTemplate.java:153)
        at org.apache.camel.impl.engine.DefaultProducerTemplate.sendBody(DefaultProducerTemplate.java:187)
        ... 2 more

Conversion of the in message to AttachmentMessage appears to be failing.
When I checked file META-INF/services/org/apache/camel/TypeConverterLoader in my assembled jar, it was missing the "org.apache.camel.attachment.AttachmentConverterLoader" entry.

If I now add the following line after starting the Camel context:

new AttachmentConverterLoader().load(ctx.getTypeConverterRegistry());

then mail sending is working fine again.

Am I doing smth wrong or is this a Camel 3.x bug?
Possible link with CAMEL-13677?