Question

How to join two lists in Java

Answer 1

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
 
public class MyClass {
    public static void main(String args[]) {
        List<String> list1 = Arrays.asList("java", "c", "c++", "python");
        List<String> list2 = Arrays.asList("c#", "go", "php");
         
        List<String> list3 = new ArrayList<>(list1);
        list3.addAll(list2);
        
        System.out.println(list3); 
    }
}
 
 
 
 
/*
run:
 
[java, c, c++, python, c#, go, php]
 
*/

 

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Answer 2

import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.Arrays;
import java.util.List;
 
public class MyClass {
    public static void main(String args[]) {
        List<String> list1 = Arrays.asList("java", "c", "c++", "python");
        List<String> list2 = Arrays.asList("c#", "go", "php");
         
        List<String> list3 = Stream.concat(list1.stream(), list2.stream())
                                            .collect(Collectors.toList());
        System.out.println(list3); 
    }
}
 
 
 
 
/*
run:
 
[java, c, c++, python, c#, go, php]
 
*/

 

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