public static String toHex(int decimalNumber) { if (decimalNumber <=0) return ""; int i=0; StringBuilder hex= new StringBuilder(); while ((int)(decimalNumber/Math.pow(16,i))>0)i++; int j=i-1; while (decimalNumber>0){ int a = (int)((decimalNumber/Math.pow(16,j))); int b= (int)(a*Math.pow(16,j)); String c = HEX.substring(a,a+1); hex.append(c); decimalNumber=decimalNumber-b; j--; } return hex.toString();