Are member variables in ONOS Component Classes thread safe and persistent. (Question)

Hi, If I want to store some state information in a Component like the L2Brideging Component, what might be the best way to do that? Can I have an array List as a data member of Component Class and store data in it and expect it to persist across all events like Device Addition event, Link Addition event etc. If so, do I need to make that array List thread safe using locks or some other mechanism.