ecco qui la ultima prova che ho fatto:


public class Elenco extends javax.swing.JFrame {

/** Creates new form Elenco */
public Elenco() {
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() {

jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
jTextField1 = new javax.swing.JTextField();

setDefaultCloseOperation(javax.swing.WindowConstan ts.EXIT_ON_CLOSE);

jButton1.setText("inserisci");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});

jButton2.setText("esci");
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(javax.swing.GroupLayout.Alignment.TRAILI NG, layout.createSequentialGroup()
.addContainerGap(96, Short.MAX_VALUE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 177, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.Component Placement.UNRELATED)
.addGroup(layout.createParallelGroup(javax.swing.G roupLayout.Alignment.LEADING)
.addComponent(jButton2)
.addComponent(jButton1))
.addGap(48, 48, 48))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout .Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILI NG, layout.createSequentialGroup()
.addContainerGap(160, Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(javax.swing.G roupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(35, 35, 35)
.addComponent(jButton2)
.addGap(45, 45, 45))
);

pack();
}// </editor-fold>

private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
System.exit(WIDTH);
}

private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
String ntelef=null;
ntelef=jTextField1.getText();
System.out.println("il numero del telefono inserito è: "+ntelef);

}

public void gestisci(){

//IL PROBLEMA È QUI: NON RICONOSCE più ntelef
System.out.println("numero di telefono: "+ntelef);
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new Elenco().setVisible(true);
}
});
Elenco el=new Elenco();
el.gestisci();
}

// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JTextField jTextField1;
// End of variables declaration

}


in una versione precedente ho messo String ntelef=null; fuori dal metodo private e allora stampa sempre null.