What's the problem.r exception

Question

guys i have written this code but a run time null pionter exception error in java.lang
is being shown in the console
guyz plz help.
here is the code
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class master extends JFrame implements ActionListener
     JPanel p1;
     JLabel l1,l2,l3;
     JTextField  t1;
     JPasswordField pw1;
     JButton b1;
     GridBagLayout g1;
     GridBagConstraints gbc;
     public master()
          super("hellcome");
           p1=new JPanel();
           g1=new GridBagLayout();
           gbc=new GridBagConstraints();
           getContentPane().add(p1);
           gbc.anchor=GridBagConstraints.NORTHWEST;
           gbc.fill=GridBagConstraints.HORIZONTAL;
           gbc.weightx=0.5;
           gbc.weighty=0.5;
           gbc.gridx=1;
           gbc.gridy=0;
           p1.setLayout(g1);
           g1.setConstraints(l1,gbc);
           l1=new JLabel("Fill out the form");
           p1.add(l1);
           gbc.gridx=1;
           gbc.gridy=1;
           l2=new JLabel("enter ur name");
           g1.setConstraints(l2,gbc);
           p1.add(l2);
           gbc.gridx=2;
           gbc.gridy=1;
           t1=new JTextField(10);
           g1.setConstraints(t1,gbc);
           p1.add(t1);
           gbc.gridx=1;
           gbc.gridy=2;
           l3=new JLabel("enter the password of ur club");
           g1.setConstraints(l3,gbc);
          p1.add(l3);
          gbc.gridx=2;
          gbc.gridy=2;
          pw1=new JPasswordField(10);
          g1.setConstraints(pw1,gbc);
          p1.add(pw1);
          gbc.anchor=GridBagConstraints.SOUTHEAST;
          JButton b1=new JButton("Submit");
          g1.setConstraints(b1,gbc);
          p1.add(b1);
          b1.addActionListener(this);
          setSize(400,400);
          setVisible(true);
     public static void main(String a[])
          master mas=new master();
     public void actionPerformed(ActionEvent e)
          JButton b=(JButton)e.getSource();
          addframe();
     public void addframe()
          JFrame f1=new JFrame("Password checking is done");
          JPanel p2=new JPanel();
          f1.getContentPane().add(p2);
          JLabel l4=new JLabel();
          p1.add(l4);
          String str=pw1.getText();
          if(str=="chelsea")
               l4.setText("Bounjeour Monsieur enjoy ur stay here");
          else
               l4.setText("Sorry monsieur ur Raison de Eitre is not valid");
          f1.setSize(400,400);
          f1.setVisible(true);
guyz cud u plz alos tell me how to post the error messages which ar shown in the
console so that i can put those error messages here.

Answer 1

thanks for ur replies ackumar and quitte
i employed both but didn't work still i am going into the
else block,maybe some logical problem still prevails in the upper part
seems like that addframe method is not getting the string.
plz see thru it.
i am again postin it with the equals method
here it is
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.util.*;
class master extends JFrame implements ActionListener
     JPanel p1;
     JLabel l1,l2,l3;
     JTextField  t1;
     JPasswordField pw1;
     JButton b1;
     GridBagLayout g1;
     GridBagConstraints gbc;
     String str;
     public master()
          super("hellcome");
           p1=new JPanel();
           g1=new GridBagLayout();
           gbc=new GridBagConstraints();
           getContentPane().add(p1);
           gbc.anchor=GridBagConstraints.NORTHWEST;
           gbc.fill=GridBagConstraints.HORIZONTAL;
           gbc.weightx=0.5;
           gbc.weighty=0.5;
           gbc.gridx=1;
           gbc.gridy=0;
           p1.setLayout(g1);
           l1=new JLabel("Fill out the form");
           g1.setConstraints(l1,gbc);
           p1.add(l1);
           gbc.gridx=1;
           gbc.gridy=1;
           l2=new JLabel("enter ur name");
           g1.setConstraints(l2,gbc);
           p1.add(l2);
           gbc.gridx=2;
           gbc.gridy=1;
           t1=new JTextField(10);
           g1.setConstraints(t1,gbc);
           p1.add(t1);
           gbc.gridx=1;
           gbc.gridy=2;
           l3=new JLabel("enter the password of ur club");
           g1.setConstraints(l3,gbc);
          p1.add(l3);
          gbc.gridx=2;
          gbc.gridy=2;
          pw1=new JPasswordField(10);
          g1.setConstraints(pw1,gbc);
          p1.add(pw1);
           str=new String(pw1.getPassword());
          gbc.anchor=GridBagConstraints.SOUTHEAST;
          JButton b1=new JButton("Submit");
          g1.setConstraints(b1,gbc);
          p1.add(b1);
          b1.addActionListener(this);
          setSize(400,400);
          setVisible(true);
     public static void main(String a[])
          master mas=new master();
     public void actionPerformed(ActionEvent e)
          JButton b=(JButton)e.getSource();
          addframe();
     public void addframe()
          JFrame f1=new JFrame("Password checking is done");
          JPanel p2=new JPanel();
          f1.getContentPane().add(p2);
          JLabel l4=new JLabel();
          p2.add(l4);
     //String st1="chelsea";
          //int i=st.compareTo(st1);
     //     String str=new String(pw1.getPassword());
          if(str.equals("chelsea"))
               l4.setText("Bounjeour Monsieur enjoy ur stay here");
          else
               l4.setText("Sorry");
          f1.setSize(400,400);
          f1.setVisible(true);
}