Join two ArrayLists in Java

Join two ArrayLists in Java

Last Updated : 16 Nov, 2024

Given two ArrayLists in Java, the task is to join these ArrayLists.

Examples:

Input: ArrayList1: [Geeks, For, ForGeeks] , ArrayList2: [GeeksForGeeks, A computer portal]
Output: [Geeks, For, ForGeeks, GeeksForGeeks, A computer portal]
Input: ArrayList1: [G, e, e, k, s] , ArrayList2: [F, o, r, G, e, e, k, s]
Output: [G, e, e, k, s, F, o, r, G, e, e, k, s]

Syntax:

ArrayList1.addAll(ArrayList2);

Implementation:

Java

import java.util.*;

public class GFG {
    public static void main(String args[])
    {

        // Get the ArrayList1
        ArrayList<String> list1 = new ArrayList<String>();

        // Populate the ArrayList
        list1.add("Geeks");
        list1.add("for");
        list1.add("Geeks");

        // Get the ArrayList2
        ArrayList<String> list2 = new ArrayList<String>();

        list2.add("GeeksForGeeks");
        list2.add("A Computer Science Portal");

        // Join the ArrayLists
        // using Collection.addAll() method
        list1.addAll(list2);

        // Print the joined ArrayList
        System.out.println(list1);
    }
}

Output

[Geeks, for, Geeks, GeeksForGeeks, A Computer Science Portal]

ArrayLists can be joined in Java with the help of Collection.addAll() method. This method is called by the destination ArrayList and the other ArrayList is passed as the parameter to this method. This method appends the second ArrayList to the end of the first ArrayList.

Join two ArrayLists in Java

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RishabhPrabhu

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