How To Visualize Values Of The Selected Row

I'm currently writing a small program, where I need to save data into a Defaulttablemodel in a jTable.I have to save the name, a number and the email-adress.I added a button which opens a new JFrame and there I need to change the email and/or the name.My current solution is far from good: No matter which row I select, i can only update the "newest" row (last created). How can I visualize the values of the selected row (out.println// or whatever) so I can go further and overwrite these values.My Code when I click on Update:

int zeilenwahl = jTableStudenttab.getSelectedRow();
// System.out.println(jTableStudenttab.getSelectedRow());
if (zeilenwahl != -1) {
this.setVisible(false);
new Bearbeitung().setVisible(true);
} else {
JOptionPane.showMessageDialog(rootPane, "Zum Bearbeiten Zeile auswählen");
}

Here is where the mistake is (probably)

public Bearbeitung() {

initComponents();
jTextFieldvorname.setText(Student.vorname);
jTextFieldnachname.setText(Student.nachname);
matrikelstring = matrikelstring.valueOf(Student.matrikelnummer);
jLabelmatrikelwert.setText(matrikelstring);
jTextFieldemail.setText(Student.email);

}