Convert Unicode into something that can be embedded in a java properties file in Java

/*from   w  w w .ja  v  a  2  s  .c  o  m*/
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 */

import java.security.SecureRandom;
import java.util.Random;

public class Main
{

  /**
   *  Converts a string from the Unicode representation into something that can be
   *  embedded in a java properties file.  All references outside the ASCII range
   *  are replaced with \\uXXXX.
   *
   *  @param s The string to convert
   *  @return the ASCII string
   */
  public static String native2Ascii(String s)
  {
      StringBuffer sb = new StringBuffer();
      for(int i = 0; i < s.length(); i++)
      {
          char aChar = s.charAt(i);
          if ((aChar < 0x0020) || (aChar > 0x007e))
          {
              sb.append('\\');
              sb.append('u');
              sb.append(toHex((aChar >> 12) & 0xF));
              sb.append(toHex((aChar >>  8) & 0xF));
              sb.append(toHex((aChar >>  4) & 0xF));
              sb.append(toHex( aChar        & 0xF));
          }
          else
          {
              sb.append(aChar);
          }
      }
      return sb.toString();
  }
  private static char toHex(int nibble)
  {
      final char[] hexDigit =
      {
          '0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'
      };
      return hexDigit[nibble & 0xF];
  }


}