NullPointerException - exception handling

Question

NullPointerException - exception handling

Navigation

#1 by (5 votes)
#2 by (0 votes)

1

I had the following error:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException

This error is generated when generating a PDF file that is already open, if it is closed it creates it but if it is open it jumps that exception. It should be controlled.

My question is: Can a try include two catch ? Can two exceptions be within a catch?

Code :

private void button_listaActionPerformed(java.awt.event.ActionEvent evt) {                                             
        try {
            ArrayList<Cliente> clientes = Conexiones.listado_clientes();
            PDF_Clientes.crearPDF(clientes);
            JOptionPane.showMessageDialog(null, "PDF generado correctamente en directorio actual.");
        } catch (DocumentException ex) {
            Logger.getLogger(Index.class.getName()).log(Level.SEVERE, null, ex);
            JOptionPane.showMessageDialog(null, "Error al crear el PDF.");
        } catch (NullPointerException npe) {
            Logger.getLogger(Index.class.getName()).log(Level.SEVERE, null, npe);
            JOptionPane.showMessageDialog(null, "El fichero está abierto. Debe cerrarlo.");
        }
    }

How should it be controlled? Is the solution fine?

The JOptionPane messages work for me but I get the following error in the console / Output:

GRAVE: null
java.lang.NullPointerException

java excepciones

asked by omaza1990 17.01.2017 в 20:01

source

2 answers

How to copy a table from one BD to another BD - SQL SERVER Count records per month in a MySQL table

score 5 · Answer 1

If , it is possible and you can do it in the following ways:

catch (IOException ex) {
     logger.log(ex);
     throw ex;
catch (SQLException ex) {
     logger.log(ex);
     throw ex;
}

Valid from java 7

catch (IOException|SQLException ex) {
        logger.log(ex);
        throw ex;
    }

Reference link for more information link

score 0 · Answer 2

In addition to the answers you have already received, the error continues to come up in the console because you have a

Logger.getLogger(Index.class.getName()).log(Level.SEVERE, null, ex);

Leaving only the JOptionPane will prevent the error in the console.