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How to copy or clone a Java ArrayList?
The clone() method of the java.util.ArrayList class returns a shallow copy of this ArrayList instance (i.e the elements themselves are not copied). Using this method, you can copy the contents of one array list to other.
Example
import java.util.ArrayList;
public class ArrayListDemo {
public static void main(String args[]) {
ArrayList<StringBuilder> arrlist1 = new ArrayList<StringBuilder>();
arrlist1.add(new StringBuilder("Learning-"));
ArrayList arrlist2 = (ArrayList) arrlist1.clone();
StringBuilder strbuilder = arrlist1.get(0);
strbuilder.append("list1, list2-both pointing to the same StringBuilder");
System.out.println("The 1st list prints: ");
for (int i = 0; i < arrlist1.size(); i++) {
System.out.print(arrlist1.get(i) + " ");
}
System.out.println("The 2nd list prints the same i.e:");
for (int i = 0; i < arrlist2.size(); i++) {
System.out.print(arrlist2.get(i));
}
}
}Output
The 1st list prints: Learning-list1, list2 - both pointing to the same StringBuilder The 2nd list prints the same i.e: Learning-list1, list2 - both pointing to the same StringBuilder
Updated on: 25-Feb-2020
1K+ Views
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