Error by console with jvm of sun

Question

Hello everybody:
I have an application makes with applets, but I get the next error by console:
java.lang.ClassCastException: sun.plugin.AppletViewer cannot be cast to java.awt.Frame
     at onda.gui.AppValidacion.init(AppValidacion.java:82)
     at sun.applet.AppletPanel.run(Unknown Source)
     at java.lang.Thread.run(Unknown Source)
I have no any cast.
I write you the init method about you look for any error. Thank very much. Regards
public void init()
//DM solo desarrollo
// txtUsuario.setText("PGAMEZRE");
// txtPassword.setText("PGAMEZRE99");
txtUsuario.setText("");
txtPassword.setText("");
//fin DM
try
appPadre = ((appPadre == null) ? this : _appPadre);
_sap = new SAPConnect();
dl = new Dialog(new Frame(),"Validaci?n del usuario",false);
td = new TextoDescriptivo();
jbInit();
_dbAccess = new DBAccess();
//Cambiado el 31-03-2000 para poder llamar a la validaci?n
//desde otro sitio que no sea la aplicaci?n
ok = new MsgBox( "", MsgBox.OKIMAGE, this, false );
stop = new MsgBox( "", MsgBox.STOPIMAGE, this, false );
ok = new MsgBox( "", MsgBox.OKIMAGE, _appPadre, false );
stop = new MsgBox( "", MsgBox.STOPIMAGE, _appPadre, false );
msg = new Mensaje( dbAccess );
catch (Exception e)
     e.printStackTrace();
txtPassword.setEchoChar( '?' );
dl.setResizable( false );
dl.setVisible( true );//comentada DM solo desarrollo 20020219
/*System.out.println("REQUEST_HEADER1:" + Entorno.REQUEST_HEADER1);
System.out.println("classes_DB_HEADER:" + Entorno.CHANGES_CLASSES_HEADER);
System.out.println("DB_HEADER:" + Entorno.CHANGES_DB_HEADER);
System.out.println("TEST_HEADER:" + Entorno.TEST_HEADER);
//try{valida();}catch(Exception excep ){}//DM solo desarrollo 20020219
}

Answer 1

Then I think that is not the source code of the class file you are running. Remove the class file (or backup somewhere else) and compile again.
Run it or run it with a debugger and step through the code to see what happens.