DefaultCamelContext#safelyStartRouteServices the following code is called:
startupListeners is a CopyOnWriteArrayList.
In the specification of Collections.sort it is stated, that an UnsupportedOperationException is thrown if the collections listiterator doesn't support the set-operation.
Sadly, the documentation of CopyOnWriteArrayList#listIterator states, that the listiterator doesn't support this operation.
As expected in this szenario, the UnsupportedOperationException is thrown during startup of the camel context if an Oracle JDK 1.8.0 with patchlevel lower than 20 is used.
In 1.8.0_20 the operation Collections#sort(List,Comparator) is rewritten to delegate to List#sort(Comparator) so it doesn't matter anymore if the lists listIterator supports the set-operation.
The issue can trivially been fixed by replacing the line by