code: private static String concat(Collection<String> col)
  	{
  		StringBuilder b = new StringBuilder();
  		boolean first = true;
  		for (String s : col)
  		{
  			if (first)
  				first = false;
  			else
  				b.append(";");
  
  			b.append(s);
  		}
  		return b.toString();
  	}
docs: Concatenates the given collection of strings into a single string where values are separated
  with a semicolon.
  @param col string collection
  @return concatenated string