title: Running a JPanel Form
body: <p>I am beginner in java. I created a <code>JPanel</code> form in java (NetBeans). then, i defined some actions such as mathematical calculations. When i ran my project, i did not get any error, but i could not see the <code>JPanel</code> form in the running time. because i did not define jform in main class. how can i define <code>JPanel</code> form in main class to show me <code>JPanel</code> form in running time.</p>
  
  <pre><code>public class NewJPanel extends javax.swing.JPanel {
  
  
      public NewJPanel() {
          initComponents();
      }
  
      @SuppressWarnings("unchecked")
      // &lt;editor-fold defaultstate="collapsed" desc="Generated Code"&gt;                          
      private void initComponents() {
  
          jLabel1 = new javax.swing.JLabel();
          jLabel2 = new javax.swing.JLabel();
          jLabel3 = new javax.swing.JLabel();
          jTextField1 = new javax.swing.JTextField();
          jTextField2 = new javax.swing.JTextField();
          jTextField3 = new javax.swing.JTextField();
          jButton1 = new javax.swing.JButton();
          jButton2 = new javax.swing.JButton();
          jButton3 = new javax.swing.JButton();
          jButton4 = new javax.swing.JButton();
          jButton5 = new javax.swing.JButton();
  
          jLabel1.setText("First Number:");
  
          jLabel2.setText("Second Number:");
  
          jLabel3.setText("Result:");
  
          jButton1.setText("Add");
          jButton1.addActionListener(new java.awt.event.ActionListener() {
              public void actionPerformed(java.awt.event.ActionEvent evt) {
                  jButton1ActionPerformed(evt);
              }
          });
  
          jButton2.setText("Subtract");
          jButton2.addActionListener(new java.awt.event.ActionListener() {
              public void actionPerformed(java.awt.event.ActionEvent evt) {
                  jButton2ActionPerformed(evt);
              }
          });
  
          jButton3.setText("Multiply");
          jButton3.addActionListener(new java.awt.event.ActionListener() {
              public void actionPerformed(java.awt.event.ActionEvent evt) {
                  jButton3ActionPerformed(evt);
              }
          });
  
          jButton4.setText("Divide");
          jButton4.addActionListener(new java.awt.event.ActionListener() {
              public void actionPerformed(java.awt.event.ActionEvent evt) {
                  jButton4ActionPerformed(evt);
              }
          });
  
          jButton5.setText("Clear");
          jButton5.addActionListener(new java.awt.event.ActionListener() {
              public void actionPerformed(java.awt.event.ActionEvent evt) {
                  jButton5ActionPerformed(evt);
              }
          });
  
          javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
          this.setLayout(layout);
          layout.setHorizontalGroup(
              layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
              .addGroup(layout.createSequentialGroup()
                  .addGap(66, 66, 66)
                  .addComponent(jButton1)
                  .addGap(45, 45, 45)
                  .addComponent(jButton2)
                  .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 69, Short.MAX_VALUE)
                  .addComponent(jButton3)
                  .addGap(27, 27, 27))
              .addGroup(layout.createSequentialGroup()
                  .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                      .addGroup(layout.createSequentialGroup()
                          .addGap(39, 39, 39)
                          .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                              .addComponent(jLabel1)
                              .addComponent(jLabel2)
                              .addComponent(jLabel3))
                          .addGap(88, 88, 88)
                          .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                              .addComponent(jTextField1, javax.swing.GroupLayout.DEFAULT_SIZE, 77, Short.MAX_VALUE)
                              .addComponent(jTextField2)
                              .addComponent(jTextField3)))
                      .addGroup(layout.createSequentialGroup()
                          .addGap(120, 120, 120)
                          .addComponent(jButton4)
                          .addGap(45, 45, 45)
                          .addComponent(jButton5)))
                  .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
          );
          layout.setVerticalGroup(
              layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
              .addGroup(layout.createSequentialGroup()
                  .addGap(39, 39, 39)
                  .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                      .addComponent(jLabel1)
                      .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                  .addGap(18, 18, 18)
                  .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                      .addComponent(jLabel2)
                      .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                  .addGap(18, 18, 18)
                  .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                      .addComponent(jLabel3)
                      .addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                  .addGap(34, 34, 34)
                  .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                      .addComponent(jButton1)
                      .addComponent(jButton2)
                      .addComponent(jButton3))
                  .addGap(18, 18, 18)
                  .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                      .addComponent(jButton4)
                      .addComponent(jButton5))
                  .addContainerGap(67, Short.MAX_VALUE))
          );
      }// &lt;/editor-fold&gt;                        
  
      private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
          double num1, num2, result;
          num1 = Double.parseDouble(jTextField1.getText());
          num2 = Double.parseDouble(jTextField2.getText());
          result = num1 + num2;
          jTextField3.setText(String.valueOf(result));
      }                                        
  
      private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
          double num1, num2, result;
          num1 = Double.parseDouble(jTextField1.getText());
          num2 = Double.parseDouble(jTextField2.getText());
          result = num1 - num2;
          jTextField3.setText(String.valueOf(result));
      }                                        
  
      private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
          double num1,num2, result;
          num1 = Double.parseDouble(jTextField3.getText());
          num2 = Double.parseDouble(jTextField2.getText());
          result = num1*num2;
          jTextField3.setText(String.valueOf(result));
      }                                        
  
      private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
          double num1, num2, result;
          num1 = Double.parseDouble(jTextField1.getText());
          num2 = Double.parseDouble(jTextField2.getText());
          result = num1 / num2;
  
      }                                        
  
      private void jButton5ActionPerformed(java.awt.event.ActionEvent evt) {                                         
          jTextField1.setText("");
          jTextField2.setText("");
          jTextField3.setText("");
      }                                        
  
  
      // Variables declaration - do not modify                     
      private javax.swing.JButton jButton1;
      private javax.swing.JButton jButton2;
      private javax.swing.JButton jButton3;
      private javax.swing.JButton jButton4;
      private javax.swing.JButton jButton5;
      private javax.swing.JLabel jLabel1;
      private javax.swing.JLabel jLabel2;
      private javax.swing.JLabel jLabel3;
      private javax.swing.JTextField jTextField1;
      private javax.swing.JTextField jTextField2;
      private javax.swing.JTextField jTextField3;
      // End of variables declaration                   
  }
  </code></pre>