IllegalStateException error

Question

why does this program give me an IllegalStateException when I run it? How can it be fixed?
import java.util.*;
import java.io.*;
import javax.swing.*;
public class FileChooser extends javax.swing.JFrame
    private final int POINTS = 1600;   
    java.util.Scanner scanner;
    java.io.File file;
    javax.swing.JTextArea     ta;
    javax.swing.JFileChooser  chooser;
    PlotPanel _plotPanel;
    DataPoint [] datapoint;
    public FileChooser (String title) throws java.io.FileNotFoundException
           super ();
     this.setSize(500, 800);
           this.setDefaultCloseOperation (javax.swing.JFrame.EXIT_ON_CLOSE);
     _plotPanel = new PlotPanel();
     this.add(_plotPanel);
           datapoint = new DataPoint[POINTS];     
           double time = 0;
           double force = 0;
           ta = new javax.swing.JTextArea (20, 30);
           chooser = new javax.swing.JFileChooser ();
           int status = chooser.showOpenDialog (null);
           if (status == javax.swing.JFileChooser.APPROVE_OPTION)
          File file = chooser.getSelectedFile ();
               scanner = new Scanner (file);
          else
       ta.setText ("No File Chosen");
          this.setVisible (true);
          } // end else
     for(int i=0; i < POINTS; i++)
     if (scanner.hasNextDouble())   
               time = scanner.nextDouble();
               force = scanner.nextDouble();
               datapoint[i] = new DataPoint(time,force);
       else
          datapoint[i] = new DataPoint(time,force);
     scanner.close();
    } // End FileChooser ()
    public static void main (String [ ] args) throws java.io.FileNotFoundException
        FileChooser app = new FileChooser("Graph");
    }  //end main
} // End FileChooser

Answer 1

Fix the indentation and the problem is obvious:for(int i=0; i < POINTS; i++)
     if (scanner.hasNextDouble())   
               time = scanner.nextDouble();
               force = scanner.nextDouble();
               datapoint[i] = new DataPoint(time,force);
       else
          datapoint[i] = new DataPoint(time,force);
     scanner.close();
}You close the Scanner within the for loop. The if statement which is inside the loop references the Scanner.