Word Scramble Not Scrambling Words

This program is supposed to shuffle the letters in the strings input, how ever it is just repeating the input. I am not sure what I am doing wrong, the issue seems to be in the scrambler function. Thank you

public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    Random r = new Random();

    while (in.hasNext()) {
        String str = in.next();
        System.out.println(str);
    }
}

//shuffle letters in word besides first and last 
public static String scrambler(String str, Random r) {

    //basic char array for input strings 
    char[] a = str.toCharArray();

    //scramble letters 
    for (int i = 0; i < a.length; i++) {
        //shuffle letters in word besides first and last 
        int j = r.nextInt(a.length);

        char temp = a[i];
        a[i] = a[j];
        a[j] = temp;
    }
    return new String(a);
}

You're not calling Scrambler method, you should write

public static void main( String[] args){

  Scanner in = new Scanner(System.in);
  Random r = new Random();
  while(in.hasNext()){
    String str = in.next();
    System.out.println(scrambler(str,r));
  }