This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
The braces are the escape syntax for stored procedures.
While using a PreparedStatement to call a stored procedure might work, it is risky because it might not. Or you could upgrade your driver and have it not work. It is better to use the intended CallableStatement subclass.