Decimal to Hex (Java)

/* this class includes example how to
 * convert Decimal to Hexadecimal value
 */

import java.lang.StringBuffer;

public class Muunnos {

    private static String hex = "0123456789ABCDEF";
    private static StringBuffer sb = new StringBuffer("");


    //Reversing the String

    public static String reverseString(String str) {
        StringBuffer sbB = new StringBuffer("");
        for (int x=str.length()-1;x>=0;x--) {
            sbB.append(str.charAt(x));
        }
        return sbB.toString();

    }

    //decimal to Hex; (Recursive method)
    public static String decimalToHex(int dec) {

        if (dec%16 !=0) {
            int result = dec/16;
            sb.append("" +hex.charAt(dec%16));
            return decimalToHex(result);
        }

        return reverseString(sb.toString());

    }

    public static void main(String[] args) {
        System.out.println("" +decimalToHex(7562));
        sb.replace(0, sb.toString().length(),"");   //Clears StribBuffer.
        System.out.println("" +decimalToHex(35631));
    }
}