String.format() throws FormatFlagsConversionMismatchException

Question

This code works fine in Java 1.6:

 public static String padLeft(String s, int n)
 {
     if (n <= 0)
         return s;
     int noOfSpaces = n * 2;
              


        

Answer 1

Since you are using # flag in format string, you should pass Formattable as an argument (doc).

Any work arounds?

Don't use # in format string?

Answer 2

You asked for a workaround; just use StringBuilder:

public static String padLeft(String s, int n) {
    if (n <= 0)
        return s;
    int noOfSpaces = n * 2;
    StringBuilder output = new StringBuilder(s.length() + noOfSpaces);
    while (noOfSpaces > 0) {
        output.append(" ");
        noOfSpaces--;
    }
    output.append(s);
    return output.toString();
}