Replace all occurrences in ArrayList in Java

This example shows how to replace all occurrences of one element in java with another using the replaceAll() of the Collections class. More formally, the method replaceAll() replaces each o object in object collections that implement the java.util.List (Vector, ArrayList, LinkedList) so that oldVal==null? o==null : ancienVal.equals(o).

public static < T> boolean replaceAll(List< T> list,

T ancienVal,

T newVal)

This method revises true if the list contains at least one instance that has been overridden.

import java.util.ArrayList; 
import java.util.Collections; 
import java.util.List; 

public class ArrayListReplaceAll {

 public static void main(String[] args) {
 
 // Create an ArrayList< String> 
 ArrayList< String> aList = new ArrayList< String> (); 
 
 //add string
 aList.add("a"); 
 aList.add("b"); 
 aList.add("a"); 
 aList.add("c"); 
 aList.add("d"); 
 aList.add("e"); 
 aList.add("a"); 
 
 System.out.println("Before"); 
 for(String e:aList)
 System.out.println(e); 

 //replace all occurrences of 'a' with 'aa'
 Collections.replaceAll(aList, "a", "aa"); 
 
 System.out.println("After"); 
 for(String e:aList)
 System.out.println(e); 
 }
}

Run:

Before
a
b
a
c
d
e
a
After
aa
b
aa
c< br />d
e
aa

References:
Java doc: the replaceAll() method of the Collections