Memory overhead of Java HashMap compared to ArrayList

Question

I am wondering what is the memory overhead of java HashMap compared to ArrayList?

Update:

I would like to improve the speed for searching fo

Answer 1

I don't know the exact number, but HashMaps are much heavier. Comparing the two, ArrayList's internal representation is self evident, but HashMaps retain Entry objects (Entry) which can balloon your memory consumption.

It's not that much larger, but it's larger. A great way to visualize this would be with a dynamic profiler such as YourKit which allows you to see all heap allocations. It's pretty nice.