1.dosya
-------------------------------------------------------------------------
import java.awt.*;
import javax.swing.*;
public class deneme {
	public deneme(){}
    public static void main( String[] args ) {
    	JDialog.setDefaultLookAndFeelDecorated(true);
        JFrame.setDefaultLookAndFeelDecorated(true);
        Toolkit.getDefaultToolkit().setDynamicLayout(true);
        System.setProperty("sun.awt.noerasebackground","true");
        try {
            javax.swing.plaf.metal.MetalLookAndFeel.setCurrentTheme( new javax.swing.plaf.metal.DefaultMetalTheme());
            UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
        }  
        catch (Exception ex ) {
            
        }
        
        JFrame frm=new panell();
       frm.setVisible(true);
       
       final int inset = 100;
        Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
	frm.setBounds ( inset, inset, screenSize.width - inset*2, screenSize.height - inset*2 );
        
         frm.pack();
        
    }
}
-------------------------------------------------------
2.dosya
------------------------------------------------------
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class panell extends JFrame {
	Container cont;
	
	
	public panell(){
		
		this.setTitle("asdasd");
		cont=getContentPane();
		addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent we){
				frmClose();
				}
			});
		
		int h=ScrollPaneConstants.HORIZONTAL_SCROLLBAR_AS_NEEDED;
		int v=ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED;
		JTextArea ta=new JTextArea(20,50);
		JPanel panel=new JPanel();
		panel.add(ta);
		JScrollPane sp=new JScrollPane(panel,v,h);
		cont.add(sp);
		
		cont.setLayout(new FlowLayout());
		}
		
	public void frmClose(){
		System.exit(0);
		}	
	
	}
Not : dosyayı adlandırırken class isimlerini kullanmayı unutmayın yoksa program class sınıfAdı is public, should be declared in a file named sınıfAdı.java seklinde bir hata meydana gelir.