public interface ArticleDAO {
    public int insertAricle(String id);
    public boolean deleteArticle(String id);
    public boolean updateArticle(Article art);
    public Article findArticle(String id);
}

public class ArticleDAOImp implements ArticleDAO{
    private Connection conn;

    public ArticleDAOImp(Connection conn) {
        this.conn = conn;
    }

    public int insertAricle(String id) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public boolean deleteArticle(String id) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public boolean updateArticle(Article art) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public Article findArticle(String id) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    public void releaseConnection(){
        try{
            this.conn.close();
        }catch(Exception e){
            e.printStackTrace();
        }        
    }
}