Salve, ho un dubbio per quanto riguarda l'inserimento di una query su una tabella.

codice:
  private String[] columnNames = {"First Name",
                                        "Last Name"};
                                        
        private Object[][] data = {
        {"Kathy", "Smith"}
        };

        public int getColumnCount() {
            return columnNames.length;
        }

        public int getRowCount() {
            return data.length;
        }

        public String getColumnName(int col) {
            return columnNames[col];
        }

        public Object getValueAt(int row, int col) {
            return data[row][col];
        }

        /*
         * JTable uses this method to determine the default renderer/
         * editor for each cell.  If we didn't implement this method,
         * then the last column would contain text ("true"/"false"),
         * rather than a check box.
         */
        public Class getColumnClass(int c) {
            return getValueAt(0, c).getClass();
        }

        /*
         * Don't need to implement this method unless your table's
         * editable.
         */
        public boolean isCellEditable(int row, int col) {
            //Note that the data/cell address is constant,
            //no matter where the cell appears onscreen.
            
                return true;
            
        }

        /*
         * Don't need to implement this method unless your table's
         * data can change.
         */
        public void setValueAt(Object value, int row, int col) {
            if (DEBUG) {
                System.out.println("Setting value at " + row + "," + col
                                   + " to " + value
                                   + " (an instance of "
                                   + value.getClass() + ")");
            }

            data[row][col] = value;
            fireTableCellUpdated(row, col);

            if (DEBUG) {
                System.out.println("New value of data:");
                printDebugData();
            }
        }

        private void printDebugData() {
            int numRows = getRowCount();
            int numCols = getColumnCount();

            for (int i=0; i < numRows; i++) {
                System.out.print("    row " + i + ":");
                for (int j=0; j < numCols; j++) {
                    System.out.print("  " + data[i][j]);
                }
                System.out.println();
            }
            System.out.println("--------------------------");
        }
    }

    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("TableDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        Prova20 newContentPane = new Prova20();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args)    {
        //Schedule a job for the event-dispatching thread:
        //creating and showing this application's GUI.
        
        
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                       
                createAndShowGUI();
            }
        });
    }
}
Questo è quello che ho trovato sulla guida oracle. Ora ho esteso il seguente codice con il seguente metodo

codice:
public String insertable(String Nometabella){
        Connection conn = null;
        Statement stmt = null;        
      
       try{
       //STEP 2: Register JDBC driver
       Class.forName("com.mysql.jdbc.Driver");

       //STEP 3: Open a connection
       System.out.println("Connecting to database...");
       conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/", "root","");

       //STEP 4: Execute a query
       System.out.println("Creating database...");
       stmt = conn.createStatement();
      
      
      String sql = "USE STUDENTS;";
            
      stmt.executeUpdate(sql);
      
                

String queryfinal="SELECT* FROM ";

String querytabella=queryfinal.concat(Nometabella).concat(";");


System.out.println(""+querytabella);

ResultSet rs = stmt.executeQuery(querytabella);


Vector<String> temp = new Vector<>();

Prova20 newdata=new Prova20();
  
     while (rs.next()) {

         
         
        
           Nome2=rs.getString("Nome");
           Cognome2=rs.getString("Cognome");
         

         
temp.addElement(Nome2);
         
Object [][]data = {
    {Nome2},{Cognome2} 
            };

datafinal=data;

System.out.println("oggetto"+newdata.datafinal);
     

     











        
//Create and set up the window.
         
         
         
          
            
             
               
               
            

       

      }
    
      
      
     

   
     System.out.println("Database created successfully...");
   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            stmt.close();
      }catch(SQLException se2){
      }// nothing we can do
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");  
    
   
   return Nometabella;
   
    }
Ora voglio sapere come passare il contenuto di datafinal sulla tabella.

il fatto e che sostituendo a posto di data datafinal mi dà errore.