Question

I am using a HashMap to cache some important data when my application starts.
This cache sometime grows and then reduced. I want to know how much memory it is taking on RAM.
Is it possible to get memory taken by a map in KB? Is there any API?

Answer 1

i’m using this method to estimate the MAP size:

public static void size(Map map) {
    try{
        System.out.println("Index Size: " + map.size());
        ByteArrayOutputStream baos=new ByteArrayOutputStream();
        ObjectOutputStream oos=new ObjectOutputStream(baos);
        oos.writeObject(map);
        oos.close();
        System.out.println("Data Size: " + baos.size());
    }catch(IOException e){
        e.printStackTrace();
    }
}