Spring mvc, не удалось прочитать JSON: невозможно десериализовать экземпляр java.util.Vector из токена START_OBJECT

Хорошо, я пытаюсь получить такой JSON

[{"username":"pippo","password":"bla"},{"username":"pluto","password":"bla"},{"username":"topolino","password":"bla"}]

Но я получаю эту ошибку:

    Resolving exception from handler [public void sequenziatore.server.presenter.LoginController.CheckLogin(java.util.Vector<sequenziatore.server.presenter.Utente>)]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not deserialize instance of java.util.Vector out of START_OBJECT token
 at [Source: org.apache.catalina.connector.CoyoteInputStream@68c40ef9; line: 1, column: 1]; nested exception is org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.Vector out of START_OBJECT token
 at [Source: org.apache.catalina.connector.CoyoteInputStream@68c40ef9; line: 1, column: 1]
Resolving exception from handler [public void sequenziatore.server.presenter.LoginController.CheckLogin(java.util.Vector<sequenziatore.server.presenter.Utente>)]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not deserialize instance of java.util.Vector out of START_OBJECT token
 at [Source: org.apache.catalina.connector.CoyoteInputStream@68c40ef9; line: 1, column: 1]; nested exception is org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.Vector out of START_OBJECT token
 at [Source: org.apache.catalina.connector.CoyoteInputStream@68c40ef9; line: 1, column: 1]
Resolving exception from handler [public void sequenziatore.server.presenter.LoginController.CheckLogin(java.util.Vector<sequenziatore.server.presenter.Utente>)]: org.springframework.http.converter.HttpMessageNotReadableException: Could not read JSON: Can not deserialize instance of java.util.Vector out of START_OBJECT token
 at [Source: org.apache.catalina.connector.CoyoteInputStream@68c40ef9; line: 1, column: 1]; nested exception is org.codehaus.jackson.map.JsonMappingException: Can not deserialize instance of java.util.Vector out of START_OBJECT token
 at [Source: org.apache.catalina.connector.CoyoteInputStream@68c40ef9; line: 1, column: 1]

И это контроллер, который я использую:

@Controller
@RequestMapping(value = "/login")
public class LoginController {
    @RequestMapping(method=RequestMethod.POST, consumes = "application/json", produces = "application/json")
    @ResponseBody
    public void CheckLogin(@RequestBody Vector<Utente> vec) {
    .....
    }

Я пытался изменить тип, который я получаю с помощью Utente [] вместо Vector, но ничего не изменилось, и настоящая проблема в том, что я не понимаю, в чем ошибка... Это JSON, который я получаю, если я меняю тип получения в String и распечатать...

{"0":{"username":"pippo","password":"bla"},"1":{"username":"pluto","password":"bla"},"2":{"username":"topolino","password":"bla"}}

Это класс Утенте

public class Utente {
    private String username=null;
    private String password=null;

    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public Utente(){}
}