New Java Programmer Needs Help Understanding What He Did Wrong With His Instantiation.

**TheTortusEatsItsOwnTail** · April 17th, 2021, 04:58 PM

Im trying to write a painfully simple program in java that involves instantiating the class that holds my JFrame as a new object.

Here is the class: Main() that is supposed to instantiate the class that contains this window
__________________________________________________ _________________________________________

package TextEditor2;
 
 
public class Main {
 
    public static void main(String[] args) {
        // TODO code application logic here
 
        System.out.println("amendment to be");
        TextEditor2.NewJFrame njf = new TextEditor2.NewJFrame();
 
    }
 
}

_____
__________________________________________________ ____________________________________
I have also tried creating the new object without accessing it as an extension of it's package name

NewJFrame njf = new NewJFrame();

NewJFrame() is simply the code generated from NetBeans' JFrame form.

__________________________________________________ ________________________________________
In both these cases the compiler produces the following output.
----------------------------------------------------------------------------------------------------------------------------------------

> Task :compileJava UP-TO-DATE
> Task :processResources NO-SOURCE
> Task :classes UP-TO-DATE

> Task :runSingle
amendment to be
----------------------------------------------------------------------------------------------------------------------------------------

The compiler then proceeds to stall indefinitely without rendering the class:NewJFrame() which compiles independently without error.
__________________________________________________ _________________________________________

Im aware that there is probably a painfully simple way to fix this but It's difficult to track down reliable sources for programming explanations.

Would someone please tell me what to do?

**Norm** · April 17th, 2021, 07:29 PM

What happens when you try to compile and execute the program?
Please copy the full text of any error messages and paste it here.

Please edit your post and wrap your code with code tags:

[code]
**YOUR CODE GOES HERE**
[/code]

to get highlighting and preserve formatting.

What environment are you working in? What programs are you using to compile and execute your code?

**TheTortusEatsItsOwnTail** · April 17th, 2021, 07:44 PM

As I mentioned earlier the compiler produces the following output.
----------------------------------------------------------------------------------------------------------------------------------------

> Task :compileJava UP-TO-DATE
> Task :processResources NO-SOURCE
> Task :classes UP-TO-DATE

> Task :runSingle
amendment to be

At that point compilation stalls indefinitely and simply does not render the JFrame.

My Development Environment is NetBeans IDE.

**Norm** · April 17th, 2021, 07:53 PM

Sorry, I have never seen that output from the javac compiler program. What program/app produces that output?
I have only worked with the javac compiler.

What is the code in the NewJFrame class? What is the code in that class's constructor expected to do?

**TheTortusEatsItsOwnTail** · April 17th, 2021, 09:43 PM

The code in the constructor for new JFrame is expected to initialize the objects to their default values
in the case of java swing those objects are known as components, they are models that are rendered into views.

Here is the code genreated by NetBeans IDE

 
 
public class NewJFrame extends javax.swing.JFrame {
 
    /**
     * Creates new form NewJFrame
     */
    public NewJFrame() {
        initComponents();
    }
 
    /**
     * This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always
     * regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {
 
        jScrollPane1 = new javax.swing.JScrollPane();
        jTextPane1 = new javax.swing.JTextPane();
        jButton1 = new javax.swing.JButton();
        jButton2 = new javax.swing.JButton();
        jScrollBar1 = new javax.swing.JScrollBar();
        jSlider1 = new javax.swing.JSlider();
 
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
 
        jTextPane1.setBackground(new java.awt.Color(153, 153, 153));
        jTextPane1.setCaretColor(new java.awt.Color(153, 255, 51));
        jScrollPane1.setViewportView(jTextPane1);
 
        jButton1.setIcon(new javax.swing.ImageIcon("AbsolutePathname")); // NOI18N
        jButton1.setText("jButton1");
 
        jButton2.setIcon(new javax.swing.ImageIcon("AbsolutePathname")); // NOI18N
        jButton2.setText("jButton2");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });
 
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(layout.createSequentialGroup()
                                .addComponent(jSlider1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                                .addGap(129, 129, 129))
                            .addGroup(layout.createSequentialGroup()
                                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 1543, javax.swing.GroupLayout.PREFERRED_SIZE)
                                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
                        .addComponent(jScrollBar1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 1484, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(31, 31, 31)
                        .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 105, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jButton2, javax.swing.GroupLayout.DEFAULT_SIZE, 635, Short.MAX_VALUE)
                        .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                        .addComponent(jSlider1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addComponent(jScrollBar1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jButton1)
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 213, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap())
        );
 
        pack();
    }// </editor-fold>                        
 
    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        // TODO add your handling code here:
    }                                        
 
    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
 
        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NewJFrame().setVisible(true);
            }
        });
    }
 
    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JScrollBar jScrollBar1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JSlider jSlider1;
    private javax.swing.JTextPane jTextPane1;
    // End of variables declaration                   
}

Again this is literally just the code that NetBeansIDE generates when a user constructs a JFrameForm.

**Norm** · April 18th, 2021, 05:40 AM

The JFrame needs for the setVisible method to be called so that it is displayed on the screen.
The NewJFrame class has a main method that calls the setVisible method. If you were to start execution of the NewJFrame class, its main method would be called and the class would display on the screen. The NewJFrame class's constructor does not call the setVisible method.
Your code in the Main class's main method needs to call the setVisible method for the instance of the NewJFrame class.

**TheTortusEatsItsOwnTail** · April 18th, 2021, 09:18 PM

Thank you so much for the help, your help fixed the issue.

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