title: detecting enter key in a button
body: <pre><code>package test;
  import java.awt.*;
  import javax.swing.*;
  
  import java.awt.event.*;
  public class swing_sample extends JFrame
  {
      //declaring our swing components
      JLabel l_name,l_pass;
      JFrame e;
      JTextField t_name;
      JPasswordField t_pass;     //A special JTextField but hides input text
      JButton button;
      Container c;
  
      //a inner class to handling ActionEvents
    public  handler2 handle;
  
      //a separate class for processing database connection and authentication
      database db;
      private JLabel lblNewLabel;
  
      swing_sample()
      {
          super("Login form");
  
          c=getContentPane();
  
          //extra classes
          db=new database();
              handle =new handler2();
  
                  //swing components
          l_name=new JLabel("Username");
          l_name.setBounds(189, 69, 153, 45);
          l_pass=new JLabel("Password");
          l_pass.setBounds(189, 151, 126, 36);
          t_name=new JTextField(10);
          t_name.setBounds(321, 75, 126, 33);
          t_pass=new JPasswordField(10);
          t_pass.setBounds(321, 147, 126, 40);
          button=new JButton("Login");
          Image img50=new ImageIcon(this.getClass().getResource("/aaaa.png")).getImage();
          button.setIcon(new ImageIcon(img50));
          button.setBounds(262, 239, 137, 53);
  
          //adding actionlistener to the button
          button.addActionListener(handle);
          getContentPane().setLayout(null);
  
          //add to contaienr
          c.add(l_name);
          c.add(t_name);
          c.add(l_pass);
          c.add(t_pass);
          c.add(button);
  
          lblNewLabel = new JLabel("");
          Image img40=new ImageIcon(this.getClass().getResource("/aaaaa.png")).getImage();
          lblNewLabel.setIcon(new ImageIcon(img40));
          lblNewLabel.setBounds(10, 75, 169, 137);
          getContentPane().add(lblNewLabel);
          //visual
          setVisible(true);
          setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
          setSize(631,412);
  
      }
      public static void main(String args[])
      {
          swing_sample sample=new swing_sample();
      }
  
      //an inner class .You can also write as a separate class
      class handler2 implements ActionListener
      {
          //must implement method
          //This is triggered whenever the user clicks the login button
          public void actionPerformed(ActionEvent ae)
          {
              //checks if the button clicked
              if(ae.getSource()==button)
              {
                  char[] temp_pwd=t_pass.getPassword();
                  String pwd=null;
                  pwd=String.copyValueOf(temp_pwd);
                  System.out.println("Username,Pwd:"+t_name.getText()+","+pwd);
  
                  //The entered username and password are sent via "checkLogin()" which return boolean
                  if(db.checkLogin(t_name.getText(), pwd))
                  {
                      //a pop-up box
                      JOptionPane.showMessageDialog(null, "You have logged in successfully","Success",
                                          JOptionPane.INFORMATION_MESSAGE);
                  }
                  else
                  {
                      //a pop-up box
                      JOptionPane.showMessageDialog(null, "Login failed!","Failed!!",
                                          JOptionPane.ERROR_MESSAGE);
                  }
              }//if
          }//method
  
      }//inner class
  }//class
  </code></pre>
  
  <p>This is my forgot password Java application, it has also a database class which does the major work, just wanna ask how to make the button recognize enter key input here, and once recognized, it does the action performed block.</p>