With this example we are going to demonstrate how to insert all elements of a Collection to a specific ArrayList index. We are using the Vector as a Collection implementation. In short, to insert all elements of a Vector to a specific ArrayList index you should:
- Create a new ArrayList.
- Populate the arrayList with elements, using
add(E e)API method of ArrayList. - Create a new Vector.
- Populate the vector with elements, using
add(E e)API method of Vector. - In order to insert all elements of the vector to the arrayList at a specific index use
addAll(Collection c)API method of ArrayList. The method appends all of the elements in the vector to the end of the arrayList, in the order that they are returned by the vector’s Iterator.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core;
import java.util.ArrayList;
import java.util.Vector;
public class InsertAllElementsOfCollectionToArrayList {
public static void main(String[] args) {
// Create an ArrayList and populate it with elements
ArrayList arrayList = new ArrayList();
arrayList.add("element_1");
arrayList.add("element_2");
arrayList.add("element_3");
// Create another Collection e.g. Vector object and populate it with elements
Vector vector = new Vector();
vector.add("vector_element_1");
vector.add("vector_element_2");
// Insert all elements of Vector to ArrayList at index 1
arrayList.addAll(1,vector);
System.out.println("Elements in ArrayList :");
for(int i=0; i < arrayList.size(); i++)
System.out.println(arrayList.get(i));
}
}
Output:
Elements in ArrayList :
element_1
vector_element_1
vector_element_2
element_2
element_3
This was an example of how to insert all elements of a Collection to a specific ArrayList index in Java.
