java - Use arraylist to store the log events in memory - with rolling appender -

i'm going extends rollingfileappender. have defined size , amount of dile in log4j.properties:

log4j.appender.myapp.maxfilesize=20mb log4j.appender.myapp.maxbackupindex=5 

my extenstion should save log event in memory , when there error, write them log.

i use arraylist<loggingevent> loggingevents = new arraylist<>();

but, don't know size give arraylist still work sizes defined above expected. suggestion?

thanks