Java: Join two array lists

Last update on May 21 2025 12:47:07 (UTC/GMT +8 hours)

15. Join Two ArrayLists

Write a Java program to join two array lists.

Pictorial Presentation:

Java Collection, ArrayList Exercises: Join two array lists

Sample Solution:-

Java Code:

import java.util.ArrayList;
import java.util.Collections;
  public class Exercise15 {
  public static void main(String[] args) {
   ArrayList<String> c1= new ArrayList<String>();
          c1.add("Red");
          c1.add("Green");
          c1.add("Black");
          c1.add("White");
          c1.add("Pink");
          System.out.println("List of first array: " + c1);
          ArrayList<String> c2= new ArrayList<String>();
          c2.add("Red");
          c2.add("Green");
          c2.add("Black");
          c2.add("Pink");
          System.out.println("List of second array: " + c2);
         
      // Let join above two list
        ArrayList<String> a = new ArrayList<String>();
        a.addAll(c1);
        a.addAll(c2);
        System.out.println("New array: " + a);
        

     }
}

Sample Output:

List of first array: [Red, Green, Black, White, Pink]                  
List of second array: [Red, Green, Black, Pink]                        
New array: [Red, Green, Black, White, Pink, Red, Green, Black, Pink]

Flowchart:

For more Practice: Solve these Related Problems:

Write a Java program to join two ArrayLists using addAll() and then remove any duplicate elements from the result.
Write a Java program to merge two ArrayLists of different types into a single ArrayList of objects and print them.
Write a Java program to join two ArrayLists and then sort the merged list using a custom comparator.
Write a Java program to use Java streams to concatenate two ArrayLists and collect the result into a new list.

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