[CAMEL-16878] using breadcrumbs can cause ClassCastException in MailBinding

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.11.2, 3.12.0
• Component/s: camel-mail
• Estimated Complexity: Unknown
• Assignee: Claus Ibsen
• Reporter: Rik van Ballegooijen
• Created: 19/Aug/21 15:50
• Updated: 21/Aug/21 10:42
• Resolved: 21/Aug/21 10:42

Description

ClassCastException: class org.apache.camel.component.directvm.DirectVmEndpoint cannot be cast to class org.apache.camel.component.mail.MailEndpoint

 

This is caused by:

 

MailConfiguration mailConfiguration = ((MailEndpoint) exchange.getFromEndpoint()).getConfiguration();

Which assumes the exchanges endpoint is always a MailEndpoint.

 

This piece of code from DefaultUnitOfWork will trigger the init of headers:

if (useBreadcrumb) {
    // create or use existing breadcrumb
    String breadcrumbId = exchange.getIn().getHeader(Exchange.BREADCRUMB_ID, String.class);
    if (breadcrumbId == null) {
        // no existing breadcrumb, so create a new one based on the exchange id
        breadcrumbId = exchange.getExchangeId();
        exchange.getIn().setHeader(Exchange.BREADCRUMB_ID, breadcrumbId);
    }
}

If message is of type MailMessage, it will be delegated there:

MailBinding binding = ExchangeHelper.getBinding(getExchange(), MailBinding.class);
if (binding != null) {
    map.putAll(binding.extractHeadersFromMail(mailMessage, getExchange()));
}

This works for the initial route with a from imaps, but in a subroute the error occurs.

 

Possible solution could be to pass a reference to either the mail endpoint or mail configuration to the binding on create/set.