Camel from(mail) loose headers?

Question

I have a problem with camel route using IMAP.

from("imap://mail.server?username=aaa&password=zzz&copyTo=out&delete=true&unseen=false&folderName=in&mapMailMessage=false")
.tracing()
.setHeader("copyTo", simple("works"))
.bean(MyTest.class, "setBodyWithHardcodedJson")
.unmarshal(new JacksonDataFormat(Reply.class))
.log("copyTo=${header[copyTo]}")

The call to setBodyWithHardcodedJson override the body with a valid json, the unmarshall is done correctly.

The last instruction prints me null value. (My header is lost between the unmarshall and the log steps)

I tried the same route, but replacing the from(imap) with a from(direct) and send something from unit test. The last instruction prints me "works" value, as expected.

Please, can somebody explain me why the exchange loose the headers i set by code when i start the route with a mail ?

EDIT : Here is a reduced version of my code to show the problem.

public class MyTest extends CamelTestSupport {
@Test
public void testInjectRequest() throws Exception {
    //just here to start the route and wait result...
    String response = "x";
    MockEndpoint mock = getMockEndpoint("mock:result");
    mock.expectedMessageCount(1);
    template.sendBody("direct:start", response);
    assertMockEndpointsSatisfied();
}
@Override
protected RoutesBuilder createRouteBuilder() throws Exception {
    return new RouteBuilder() {
        @Override
        public void configure() throws Exception {
            // activate next line to start with direct -> works
            //from("direct:start")
            // activate next line to start with mail : test fails (not important) 
            // BUT PROBLEM : different result of .log("copyTo=${header[copyTo]}")
            from("imap://server?username=aaa&password=bbb&copyTo=out&delete=true&unseen=false&folderName=in&mapMailMessage=false")
                .tracing()
                     .onException(Exception.class)
                     .log("exception here ${exception.message}")
                .end()
                .setHeader("copyTo", simple("works"))
                .bean(MyTest.class, "hardcodeJson")
                .unmarshal(new JacksonDataFormat(Reply.class))
                .log("body=${body.id}")
                .log("copyTo=${header[copyTo]}")
            ;
        }
    };
}
protected void hardcodeJson(Exchange exchange) {
    String jsonInputString = "{\n" +
            "   \"id\": \"Corresp_Rest:3e9a525d-fc64-\"\n" +
            "}";
    exchange.getIn().setBody(jsonInputString);
}
}

public class Reply {
String id;

public String getId() {
    return id;
}

public void setId(String id) {
    this.id = id;
}
}

Info following questions from @kladderradatsch

in the traces i find :

INFO  route1 - body=Corresp_Rest:3e9a525d-fc64-
INFO  route1 - copyTo=

if i do it with from(direct) i have

INFO  route1 - body=Corresp_Rest:3e9a525d-fc64-
INFO  route1 - copyTo=works

I hardcoded the json body in the bean to be sure it should unmarshal the same way, independent of the from().

After the unmarshal, the body is a Reply object with the content OK, but the headers modified are resetted only on from("imap"), not on from("direct").

Maybe i'm wrong, but i imagine the unmarshall provoques something in camel-mail to recreate the exchange from original message, losing the changes in headers made by my code...

Answer 1

Rename your header copyTo to any other name because copyTo is an option of the imap: component so this clashes.