gistfile1.java

Person p = new Person();
p.set("first_name", "Marilyn","last_name", "Monroe");
p.set("dob", "1926/6/1");                     //wrong format
p.validate();
System.out.println(p.errors().get("dob"));    //prints out: attribute dob does not conform to format: yyyy-MM-dd

p.set("dob", "1926-06-01");                   //right format
p.validate();
System.out.println(p.get("dob").getClass()); //prints out: class java.sql.Date
System.out.println(p.get("dob"));            //prints out: 1926-06-01