There is a list which is holding 300,000 objects all the time, which won't be cleaned by gc. 

If the jvm configuration "Xmx" have a big enough value, will this big list make gc have a bad performance? 

I'm asking this because I want to use a big list and data cache in my application. If a big list doesn't affect GC, it's the best choice to do this, because a list in jvm has better performance than others, e.g. memcached, memory db,