depak khatri

i am making a prog to enter values in a textfield array and sum all those values but
i am getting null pointer exception when i click on sum button and clear button
please help me out
import java.awt.*; import java.applet.*; import java.awt.event.*; //<applet code="M"width="700"height="700"></applet> public class M extends Applet implements ActionListener { Button sum; Button avg; Button clear; static final int n=4; int s[]=new int[n]; int p; String f= ""; TextField t[][]=new TextField[n][n]; public void init() { setLayout(new GridLayout(n,n)); setFont(new Font("SansSerif",Font.BOLD,14)); for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { t=new TextField[n][n]; t[i][j]=new TextField(); add(t[i][j]); } } sum=new Button("Column Sum"); avg=new Button("Column average"); clear=new Button("Clear"); add(sum); add(avg); add(clear); sum.addActionListener(this); avg.addActionListener(this); clear.addActionListener(this); } public void actionPerformed(ActionEvent e) {Object obj=e.getSource(); if(obj==clear) { for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { t[i][j].setText(f); } } } if(obj==sum) { for(int j=0;j<n;j++) { for(int i=0;i<n;i++) { int a = Integer.parseInt(t[i][j].getText()); s[j]=a; } } for(int i=0;i<n;i++) { for(int j=0;j<n;j++) { t[i][j].setText(""); } } p=n-1; for(int j=0;j<n;j++) { String a=Integer.toString(s[j]); t[p][j].setText(a); } } } }

i want to make an application where two computers are connected through lan and on the client computere i want to
provide a form, from where i can control the cursur on the other computer
what ever one can do on a computer i should be able to do on that form
like
open a folder
opening an application
its like providing a platform to operate another computer
without using hardware of that computer
and sorry for posting in the wrong forum actually i was confused and i just write it

i want to make an remote desktop application
can someone help me
please tell me which java class's i need to build this application

i have changed my name as per your guidelines says no funny names now will you please help me
now with my problem

i am using netbeans 6.8 and while running my program an error "build-impl.xml:577: The module has not been deployed" occured . my web.xml file is shown below
<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <context-param> <param-name>no</param-name> <param-value>100203231982381</param-value> </context-param> <servlet> <servlet-name>servlet1</servlet-name> <servlet-class>servlet1</servlet-class> </servlet> <servlet> <servlet-name>listener</servlet-name> <servlet-class>listener</servlet-class> </servlet> <servlet-mapping> <servlet-name>servlet1</servlet-name> <url-pattern>/s1</url-pattern> </servlet-mapping> <servlet-mapping> <servlet-name>listener</servlet-name> <url-pattern>/l1</url-pattern> </servlet-mapping> <listener> <listener-class>listener</listener-class> </listener> <session-config> <session-timeout> 30 </session-timeout> </session-config> </web-app>
i am trying to use context parameter in my servlets there are two servlets first one is listener.java which implements ServletContextListener and another is servlet1.java i dont undertand the error everything is fine in both the files please help me