Regarding the Resequencer component, the documentation Implementing Enterprise Integration Patterns says that:

You can also use multiple expressions to sort messages in a batch. For example, if you want to sort incoming messages, first, according to their JMS priority (as recorded in the JMSPriority header) and second, according to the value of their time stamp (as recorded in the TimeStamp header), you can define a route like the following:

from("direct:start").resequence(header("JMSPriority"), header("TimeStamp")).to("mock:result");

In this case, messages with the highest priority (that is, low JMS priority number) are moved to the front of the batch. If more than one message has the highest priority, the highest priority messages are put in order according to the value of the TimeStamp header.

However, multiple expressions are disabled since Camel 2.7.0 due to CAMEL-3696. So drop the above block from the documentation so that users won't be confused.