Thread: Where does the program start?

Hi all,
I am a newbie to java and hence I have been using online examples to learn how to code java. One big problem I am having is where in the code does the program actually start. I have a java swing code in which I want to call a subroutine to read in some settings from a text file on start up either before or just after the main frame is set visible.

eg

private void someroutine(){
}

I have tried to call the routine from various locations in the main statement below but I get is the error
"non-static method readSettings() cannot be referenced from a static context"

Any help will be apprieciated.


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
* How to Set the Look and Feel (The Java™ Tutorials > Creating a GUI With JFC/Swing > Modifying the Look and Feel)
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClass Name());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(ContactEditorUI .class.getName()).log(java.util.logging.Level.SEVE RE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(ContactEditorUI .class.getName()).log(java.util.logging.Level.SEVE RE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(ContactEditorUI .class.getName()).log(java.util.logging.Level.SEVE RE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(ContactEditorUI .class.getName()).log(java.util.logging.Level.SEVE RE, null, ex);
}
//</editor-fold>

/*
* Create and display the form
*/
java.awt.EventQueue.invokeLater(new Runnable() {

@Override
public void run() {
new ContactEditorUI().setVisible(true);

}
});
}

yes I want to call it from within the main method, I call call it from a button click ok but it needs to be called when the code starts.

I have tried private static void somerouine() but netbeans compalined :-(

Java is by far the hardest language I have had to learn and I just can't get to grips with it's structure.

any way how do I delare to method and where do I call it from within the main method?

I have declared it a public static void but now netbeans complains about all the variables I am using

non-static variable xxxxx cannot be referenced from a static context

Originally Posted by aussiemcgr

Yeah, that'll happen. It has to do with what the word static means. I don't know about what others do, but it is for that reason that I try to limit the amount I do in the main. For example, if I was creating a class that had the main, I would do something like:

public class SomeClass {
 
	private int var = 0;
 
	public SomeClass(int value) {
		var = value;
	}
 
	public int getVar() {
		return var;
	}
 
	public static void main(String[] args) {
		Someclass obj = new SomeClass(5);
		System.out.println("Var value: "+obj.getVar());
	}
}

By creating an Object, doing all of the work in the Object instead of the main, and then creating that Object in the main, you can avoid all of that static nonsense.

Ok the main method in my code displays the java swing frame but all I want to do is call one method before to read in some setting from a text file so they can be displayed when the frame is made visible.

eg.
program starts
call the getsettings method
display the frame

heres the chunk of code in question

    public void readSettings() {
 
        try{
            // Open the file that is the first 
            // command line parameter
            FileInputStream fstream = new FileInputStream("c:\\settings.txt");
            // Get the object of DataInputStream
            DataInputStream in = new DataInputStream(fstream);
            BufferedReader br = new BufferedReader(new InputStreamReader(in));
            String strLine;
            //Read File Line By Line
            server = br.readLine();
            userName = br.readLine();
            module = br.readLine();
            port = Integer.parseInt(br.readLine());
            source1 = br.readLine();
            source2 = br.readLine();
            log = br.readLine();
            passwordFile = br.readLine();
            //Close the input stream
            in.close();
        }catch (Exception e){
            }
 
        // Dispaly setings in text boxes
        jTextServer.setText(server);
        jTextUserName.setText(userName);
        jTextModule.setText(module);
        jTextPort.setText(Integer.toString(port));
        jTextSource1.setText(source1);
        jTextSource2.setText(source2);
 
    }
 
    /**
     * @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
         * [url=http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html]How to Set the Look and Feel (The Java™ Tutorials > Creating a GUI With JFC/Swing > Modifying the Look and Feel)[/url]
         */
        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(ContactEditorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(ContactEditorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(ContactEditorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(ContactEditorUI.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>
 
        /*
         * Create and display the form
         */
        java.awt.EventQueue.invokeLater(new Runnable() {
 
            @Override
            public void run() {
                new ContactEditorUI().setVisible(true);
 
            }
        });
    }

how do i implement calling getsettings() method in the main method? Sorry for being a pain but I am having trouble with how call methods and classes in java, perhaps I should have stuck with C..