Netflix/RxJava — pull request #1388 by mattrjacobs (2014-06-25 22:53:28+00:00)
Title: CompositeException stops mutating nested Exceptions

Instead, it aggregates them at print-time. Since nothing is being mutated, there's no chance of accidentally creating a cycle in the Exception chain. We ran into this in production very intermittently and had to add handling any time we were touching the Exception chain.