ExampleProcessor.java

class ExampleProcessor implements Processor {

    @Override
    public void process(Exchange exchange) throws Exception {
        try {
            // do your transformation here
        } catch (ExampleException e) {
            final List<ExampleException> allExceptions = Optional
                .ofNullable(exchange.getProperty("all-exceptions", List.class)).orElseGet(ArrayList::new);

            allExceptions.add(e);

            exchange.setProperty("all-exceptions", allExceptions);
        }
    }

}