public class apples
{
   public static void main(String args[])
   {
      Scanner input = new Scanner(System.in);
      StringBuffer sb = new StringBuffer(input.nextLine());

      String  s = sb.toString();
      char[] c = s.toCharArray();
      //LinkedList<char> l = new LinkedList<char>(Arrays.asList(c));
      /* giving error "Syntax error on token " char",
         Dimensions expected after this token"*/
    }
}

public static void main(String[] args) {
    String s = "asdasdasda";
    char[] chars = s.toCharArray();

    //      List<Character> list = Arrays.asList(chars); // this does not compile,
    List<char[]> asList = Arrays.asList(chars); // because this DOES compile.

    List<Character> listC = new ArrayList<Character>();
    for (char c : chars) {
        listC.add(c);
    }
}

Character[] array = listC.toArray(new Character[listC.size()]);

private static String replaceWhitespaces(String string, String replacement) {
    return string != null ? string.replaceAll("\s", replacement) : null;
}

StringBuffer s = new StringBuffer("Mike is good");
System.out.println(replaceWhitespaces(s.toString(), "%20"));

Mike%20is%20good

LinkedList<Character> characterList = new LinkedList<Character>(Chars.asList(string.toCharArray()));

LinkedList<Character> characterList = Lists.newLinkedList(Chars.asList(string.toCharArray()));

List<Character> list = Arrays.asList(c);