According to my knowledge your solutions will update only references, as does Collection.copy()
. You can use the below method, which I prefer:
List<ArrayList<PointF>> newList = new ArrayList<ArrayList<PointF>>(oldList);
A change of the old list would not affected to new list.
I tested your second option and it also has the property that changes to the old one will not affect the new List.
Note - These will also update only the references. If you change elements in your new list it will update old list too. I think Your second array will create brand new objects, but I am not 100% sure about that. I am adding my testing code below for you reference.
package test;
import java.util.ArrayList;
import java.util.List;
/**
* Created by Lasitha Benaragama on 4/28/14.
*/
public class StckTest {
public static void main(String[] args) {
List<String> oldList = new ArrayList<String>();
oldList.add("AAAAA");
oldList.add("BBBBB");
oldList.add("CCCCC");
oldList.add("DDDDDD");
oldList.add("EEEEEE");
StckTest test = new StckTest();
List<String> newListCopy = new ArrayList<String>(oldList);
List<String> newListClone = new ArrayList<String>();
for(int i = 0; i < oldList.size(); i++)
newListClone.add(oldList.get(i));
test.printArray(newListCopy);
test.changeList(oldList);
test.printArray(oldList);
test.printArray(newListCopy);
test.printArray(newListClone);
}
public void changeList(List<String> oldList) {
oldList.remove(2);
oldList.add("FFFFF");
}
public void printArray(List<String> oldList){
for(int i = 0; i < oldList.size(); i++){
System.out.print(oldList.get(i)+",");
}
System.out.println();
}
}