// You cannot change the characters of a string in java
// But you can make it work
// For Example: A Program to change 'r' to 'a'
class Main{
public static void main(String args[]){
String str = "return";
String res = "";
for(int i = 0; i<str.length(); i++){
if(str.charAt(i)=='r'){
res+='a';
}
else{
res+=str.charAt(i);
}
}
System.out.print("Result = "+res);
}
}