Creare una finestra in java

Creare una finestra in java
CODICE:

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Finestra.java
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import javax.swing.*;
/**
* Write a description of class Finestre here.
*
* @author (your name)
* @version (a version number or a date)
*/
public class Finestra
{
JFrame finestra;

public Finestra(String f_nome,int x,int y)
{
finestra=new JFrame(f_nome);
finestra.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
finestra.setSize(x,y);
finestra.setVisible(true);
}
public void setSize(int x,int y){
finestra.setSize(x,y);
}
public void visualizza(){
finestra.setVisible(true);
}
public void nascondi(){
finestra.setVisible(false);
}



}

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TestaFinestra.java
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public class TestaFinestra
{
public static void main(String[] args){
Finestra c1=new Finestra("F1",500,200);
/* c1.setSize(800,600); metodo in piu' */
}
}