Thread: Illegal start of expression

import javax.swing.*;
class Window extends JFrame
{
public static void main ( String[] args)
{
JPanel pnl = new JPanel() ;
public Window()
{
super( "Swing Window" ) ;
setSize( 500, 200 ) ;
setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
add( pnl ) ;
setVisible( true ) ;
}
Window gui = new Window() ;
}
}

According to Bluej, the public Window() is in correct, with the specific error being "illegal start of expression". Any ideas where I went wrong?

import javax.swing.*;
class Window extends JFrame
{
    public static void main ( String[] args)
    {
        JPanel pnl = new JPanel() ;
        public Window()
        {
            super( "Swing Window" ) ;
            setSize( 500, 200 ) ;
            setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
            add( pnl ) ;
            setVisible( true ) ;
        }
        Window gui = new Window() ;
    }
}

The exact error I get is "illegal start of expression" with public Window() being highlighted. Thanks in advance for the help.

I tried changing the class name, but it didn't seem to make a difference.

I tried compiling it through the command prompt, and got the following results:

Window.java:7: error: ';' expected
public Window()
^
2 errors

So I added the ';' and got the following error back.

Window.java:7: error illegal start of expression
public Window();
^
1 error

the book I'm using reads as follows:

1) Start a new program that imports all Swing components

import javax.swing.* ;

2)Create a subclass of the JFrame class named "Window" containing the standard main method

class Window extends JFrame
{
           public static void main ( String[] args ) {}
}

3) before the main method, create a JPanel container object

JPanel pnl = new JPanel();

4) Next insert this constructor method to specify window requirements and to add the JPanel object to the JFrame

public Window()
{
            super( "Swing Window" ) ;
            setSize( 500, 200 ) ;
            setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
            add( pnl ) ;
            setVisible( true ) ;
        }

5) Create an instance of the Window class by inserting this line into the main method

Window gui = new Window();

Sorry Norm, but I'm having allot of trouble with this.....I gather my original code is arranged wrong due to the placement of my {s? How should they be arranged?

Originally Posted by Tedstriker

the book I'm using reads as follows:

1) Start a new program that imports all Swing components

import javax.swing.* ;

2)Create a subclass of the JFrame class named "Window" containing the standard main method

class Window extends JFrame
{
           public static void main ( String[] args ) {}
}

3) before the main method, create a JPanel container object

JPanel pnl = new JPanel();

4) Next insert this constructor method to specify window requirements and to add the JPanel object to the JFrame

public Window()
{
            super( "Swing Window" ) ;
            setSize( 500, 200 ) ;
            setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
            add( pnl ) ;
            setVisible( true ) ;
        }

5) Create an instance of the Window class by inserting this line into the main method

Window gui = new Window();

So I've been messing around with this. While its still wrong, at least I got a different error (class, interface, or enum expected with the ^ under the word void) with this effort:

import javax.swing.*;
class Note extends JFrame
{
      JPanel pnl = new JPanel() ;
    }
    public static void main ( String[] args)
    {
 
 
        public Window() 
        {
            super( "Swing Window" ) ;
            setSize( 500, 200 ) ;
            setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
            add( pnl ) ;
            setVisible( true ) ;
        }
        Window gui = new Window() ;
    }

am I getting warmer?

Thanks Norm, but reading that just doesn't make sense to me. When it says JPanel pnl = newJPanel(); goes before the main method, where would that be? where would the different methods begin and end. Sorry, but I'm having trouble with this one.

import javax.swing.*;
class Note extends JFrame
//beginning of class
{       
    public static void main ( String[] args) 
    //beginning of main method
    {
       JPanel pnl = new JPanel() ;
        Window gui = new Window() ;
        //end of main method
    }
        public Window()
        //beginning of next method
        {
            super( "Swing Window" ) ;
            setSize( 500, 200 ) ;
            setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
            add( pnl ) ;
            setVisible( true ) ;
            //end of next method
        }
 
 
    //end of the class
}

added some notes

Now I get this error:
public Window()
^

invalid method declaration; return type required

Ok, corrected that...looks like its getting better. However, I now get the following error:

add ( pnl ) ;
^

cannot find symbol - variable pnl

import javax.swing.*;
class Window extends JFrame
//beginning of class
{     
    JPanel pnl = new JPanel() ;
    public static void main ( String[] args) 
    //beginning of main method
    {
 
       Window gui = new Window() ;
        //end of main method
    }
    public Window()
        //beginning of next method
    {
       super( "Swing Window" ) ;
       setSize( 500, 200 ) ;
       setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
       add( pnl ) ;
       setVisible( true ) ;
            //end of next method
    }
 
 
    //end of the class
}

This worked!! I created my little window! Thanks Norm, I appreciate the help. Till next time.....

Thought I would post in this thread instead of creating a new one, as my question is related. The next part of the book I'm working with is to add buttons to the window created. The following is my code:

import javax.swing.*;
class Buttons extends JFrame
//beginning of class
{     
 
    JPanel pnl = new JPanel() ;
    public static void main ( String[] args) 
    //beginning of main method
    {
 
       Buttons gui = new Buttons() ;
 
        //end of main method
    }
    ImageIcon tick = new ImageIcon( "tick.png" );
    ImageIcon cross = new ImageIcon( "cross.png" );
    JButton btn = new JButton( "Click Me" );
    JButton tickBtn = new JButton( tick );
    JButton crossBtn = new JButton( "Stop", cross );
    public Buttons()
        //beginning of next method
    {
       super( "Swing Window" ) ;
       setSize( 500, 200 ) ;
       setDefaultCloseOperation( EXIT_ON_CLOSE ) ;
       add( pnl ) ;
       setVisible( true ) ;
       pnl.add( btn );
       pnl.add( tickBtn );
       pnl.add( crossBtn );
            //end of next method
    }
 
 
    //end of the class
}

Everything works, except the images of the cross and the tick do not load. any suggestions would be appreciated.