public static String getUniqueBoundaryValue() 
{
                                         
	StringBuffer s = new StringBuffer();
	// Unique string is ----=_Part_< part >_< hashcode >.< currentTime >
	s.append("----=_Part_").append(getUniqueId()).append("_").
	  append(s.hashCode()).append('.").
	  append(System.currentTimeMillis());
	return s.toString();
}

Get a unique value for use in a multipart boundary string. This implementation generates it by concatenating a global part number, a newly created object's hashCode(), and the current time (in milliseconds).

 public static String getUniqueMessageIDValue(Session ssn) 
{
	String suffix = null;
	InternetAddress addr = InternetAddress.getLocalAddress(ssn);
	if (addr != null)
	    suffix = addr.getAddress();
	else {
	    suffix = "javamailuser@localhost"; // worst-case default
	}
	StringBuffer s = new StringBuffer();
	// Unique string is < hashcode >.< id >.< currentTime >.JavaMail.< suffix >
	s.append(s.hashCode()).append('.").append(getUniqueId()).append('.").
	  append(System.currentTimeMillis()).append('.").
	  append("JavaMail.").
	  append(suffix);
	return s.toString();
}

Get a unique value for use in a Message-ID. This implementation generates it by concatenating a newly created object's hashCode(), a global ID (incremented on every use), the current time (in milliseconds), the string "JavaMail", and this user's local address generated by InternetAddress.getLocalAddress(). (The address defaults to "javamailuser@localhost" if getLocalAddress() returns null.)