JTextField only accepting numeric values

JNumberTextField.java

/**
 * A {@link JTextField} that skips all non-digit keys. The user is only able to enter numbers.
 * 
 * @author Michi Gysel <michi@scythe.ch>
 * 
 */
public class JNumberTextField extends JTextField {
    private static final long serialVersionUID = 1L;

    @Override
    public void processKeyEvent(KeyEvent ev) {
        if (Character.isDigit(ev.getKeyChar())) {
            super.processKeyEvent(ev);
        }
        ev.consume();
        return;
    }

    /**
     * As the user is not even able to enter a dot ("."), only integers (whole numbers) may be entered.
     */
    public Long getNumber() {
        Long result = null;
        String text = getText();
        if (text != null && !"".equals(text)) {
            result = Long.valueOf(text);
        }
        return result;
    }
}

Unfortunately this code doesn't prevent the user from entering characters through copy paste.

Unfortunately this code doesn't prevent the user from entering characters through copy paste.

same here.
i need a code that a jtextfield accept numbers(or hex numbers) but doesnt accept non-numeric from copy paste

char c = evt.getKeyChar();

    if (!(Character.isDigit(c) || c == KeyEvent.VK_BACK_SPACE || c == KeyEvent.VK_DELETE) || contactMobile.getText().length() == 10) {

        evt.consume();

    }