Find out e=1+1/1!+1/2!+1/3!+......+1/n!+ ... The approximate value of Java applet program

Program//Find out e=1+1/1!+1/2!+1/3!+......+1/n!+ ... The approximate value, the request error is less than 0.0001import java.applet.*;import java.awt.*;import java.awt.event.*;p ublic class At1_1 extends Applet Implements Actionlistener{  textfield Text1; button button1;  public void init ()  {   text1 = new TextField ("0");   button1 = new Button ("purge");   add (Text1);   Add (Button1);   text1.addactionlistener (this);   button1.addactionlistener (this);  }  public void Start () {} public void Stop () {} public void Destory () {} public void paint (Graphics g) & nbsp {   g.drawstring (Enter number n back in text area, 10,100);   g.drawstring ("Text area displays 1+1/1!+1/2!+1/3!+......+1/n! + ... Approximate value ", 10,120);  } public void actionperformed (ActionEvent e)  {  if (E.getsource () ==text1)   {   double Sum=1,a=1;   int I=1;   int n=0;    try   {   n = IntegEr.valueof (Text1.gettext ()). Intvalue ();    while (i<=n)    {      a = A * (1.0/i);     sum = sum + a;    i=i+1;   }    sum=sum*10000;   sum=math.round (sum);   sum=sum/10000;    text1.settext ("" +sum);      }   catch (NumberFormatException Event)    {   text1.settext ("Please enter numeric characters");   }  }   else if (E.getsource () ==button1)   {   text1.settext ("0");  }  &NBSP;&NBSP}}