This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
No need? Numbered parameters work just fine with "?" characters, why add to the complexity of accepted values in SQL statements? Any more and you could interfere with parsing leading to all sorts of errors in the real world. In fact, even "?" characters can cause problems as I've recently discussed.
Keep in mind, java is not based on pure theory, designed by a bunch of geniuses in a think tank... its partially based on practical use in real systems.