Как распечатать формат json на консоль с помощью bean

Я преобразовываю объект в json с интеграцией spring.

<int-jdbc:inbound-channel-adapter query = "SELECT * FROM posts" row-mapper = "postMapper"
                                      channel = "dataInbound" data-source = "dataSource">
        <int:poller fixed-rate = "5000" />
    </int-jdbc:inbound-channel-adapter>

    <int:channel id = "dataInbound" />

    <int:object-to-json-transformer input-channel = "dataInbound" output-channel = "printing"/>
    <int:service-activator id = "printing" method = "print"
                           input-channel = "print" ref = "eventActivator"/>
 <bean id = "postMapper" class = "com.example.domain.PostsMapper"/>

    <bean id = "eventActivator" class = "com.example.Dispatcher"/>
public class Posts {

    private String id;
    private String title;
    private String author;
   ...Constructor and setters/getters...
}

public class PostsMapper implements RowMapper<Posts> {

    public Posts mapRow(ResultSet rs, int rowNum) throws SQLException{
        String id = rs.getString("id");
        String title = rs.getString("title");
        String author = rs.getString("author");
        return new Posts(id, title, author);
    }
}

Но как вывести трансформер в консоль <int:service-activator>. Ну, я попробовал это, но это не сработало:

 public void print(List<Posts> posts){
        for (Posts post: posts){
            System.out.print("\n***** " + post);
        }
    }

Ошибки, которые я получаю:

Failed to convert from type [java.util.ArrayList<?>] to type [java.util.List<com.example.domain.Posts>] for value '[{id=1, title=test, author=me}]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.util.LinkedHashMap<?, ?>] to type [com.example.domain.Posts]
No converter found capable of converting from type [java.util.LinkedHashMap<?, ?>] to type [com.example.domain.Posts]
Problem invoking method: public void com.example.Dispatcher.print(java.util.List)

Так как же должен выглядеть мой bean для печати на консоли?