Question

How to keep (retain) only certain elements in ArrayList and remove the rest in Java

Answer 1

import java.util.*; 
   
public class MyClass {
    public static void main(String args[]) {
        ArrayList<String> al = new ArrayList<String>(Arrays.asList("java","c","c#","f#","php","c")); 
  
        ArrayList<String> retains = new ArrayList<>();
        retains.add("c");
        retains.add("java");
        retains.add("php");

        al.retainAll(retains);
         
        for (String s : al) {
            System.out.println(s);
        }
    }
}



/*
run:

java
c
php
c

*/

 

70+ SQL courses for beginners and professionals