Question: I need to print a String letter by letter with a \* between each letter.
I want to find a recursive solution and not an iterative one. The signature must be :

```java
public static String allStar(String a);

```

Answer: 
Try this where first the string is split into array of strings of each character and then joined together with a `*` character in between them.

```
System.out.println(String.join("*",  a.split("")));

```
try this code :

```
public class Main {

static String Answer = "" ;

    public static void main(String[] args) {

        Main.SetStarAfterEachLetter("hello!");

        System.out.println(Answer);

    }

public static void SetStarAfterEachLetter(String letter){

    Answer = Answer + letter.charAt(0);
    Answer = Answer + " * ";
    letter = letter.substring(1);

    if(!letter.isEmpty()) {
        SetStarAfterEachLetter(letter);
    }
}

```

}