Java ArrayList trimToSize() Method
trimToSize() method is used for memory optimization. It trims
the capacity of ArrayList to the current list size.
public void trimToSize()
Given arraylist is having capacity of 10 but there are only 3
elements in it, calling trimToSize() method on this ArrayList would change the
capacity from 10 to 3.
class TrimToSizeExample
{
public static void main(String args[]) {
ArrayList<Integer> arraylist = new ArrayList<Integer>(10);
arraylist.add(1);
arraylist.add(2);
arraylist.add(3);
// debug and find
that the capacity of array list is 10
//
[1, 2, 3, null, null, null, null, null, null, null]
System.out.println(arraylist.size());
arraylist.trimToSize();
// debug and find
that the capacity of array list is 3
//
[1, 2, 3]
System.out.println(arraylist.size());
}
}
Output:
3
3
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