Exception is not being captured

Question

I have a program where you can input name, surname, id and export them to a text file. The file can be imported back by using a load method. The problem with the load method is if you press the load button and don't select a file the list of errors will appear. I need to create an exception for these errors so the user will receive "Please Select a file" warning instead. So I created a custom exception:

    public class CancelException extends Exception {

    public CancelException() {
    }

    public CancelException(String message) {
        super(message);
    }

}

Then I tried to put it in the load method:

public static Person loadcons() throws IOException, CancelException {
    Person loadcons = null;
    try {
        JFileChooser chooser = new JFileChooser();
        int chooserOption = chooser.showSaveDialog(null);
        chooserOption = JFileChooser.APPROVE_OPTION;

        File file = new File(chooser.getSelectedFile().getAbsolutePath());
        ObjectInputStream input = new ObjectInputStream(new FileInputStream(file));

        loadcons = (Person) input.readObject();
        input.close();
        return loadcons;

    } catch (IOException ex) {
        System.out.println(ex.getMessage());
    } catch (ClassNotFoundException ex) {
        System.out.println(ex.getMessage());
    } catch (Exception ex) {
        throw new CancelException("Please select a file");
    }
    return null;

}

private String toString(String PersonID) {
    throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

The problem is that the exception is not being recognized and it is still giving me the exception stack trace instead of the warning.

The list of errors are below:


    Aug 17, 2015 12:41:50 PM ryan_assignment_sit2.CreateConsultant    jButton3ActionPerformed
   SEVERE: null
    ryan_assignment_sit2.CancelException: Please select a file
    at ryan_assignment_sit2.Person.loadcons(Person.java:105)
    at ryan_assignment_sit2.CreateConsultant.jButton3ActionPerformed(CreateConsultant.java:218)
    at ryan_assignment_sit2.CreateConsultant.access$300(CreateConsultant.java:29)
    at ryan_assignment_sit2.CreateConsultant$4.actionPerformed(CreateConsultant.java:87)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6525)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
    at java.awt.Component.processEvent(Component.java:6290)
    at java.awt.Container.processEvent(Container.java:2234)
    at java.awt.Component.dispatchEventImpl(Component.java:4881)
    at java.awt.Container.dispatchEventImpl(Container.java:2292)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
    at java.awt.Container.dispatchEventImpl(Container.java:2278)
    at java.awt.Window.dispatchEventImpl(Window.java:2750)
    at java.awt.Component.dispatchEvent(Component.java:4703)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

and what does the exception say? Also why do you use the throws clause on the method and seperatly on the try catch block? — SomeJavaGuy, Aug 17 '15 at 10:42
What I see is you are getting `CancelException` at your stackTrace - so as the `throws` clause says your exception is being thrown. May be you don't catch it in a `loadcons()` caller method. — itwasntme, Aug 17 '15 at 11:01
And just for info, if an exception is throw the variables in try clause aren't being initialized. So your `Person loadcons` variable sill will be `null` after an exception. — itwasntme, Aug 17 '15 at 11:04

score 1 · Accepted Answer · answered Aug 17 '15 at 11:24

1

You can just check whether the file is selected or not by adding following condition:

if (chooser.getSelectedFile() == null)
{
     JOptionPane.showMessageDialog(null, "Please select a file", "No file selected", JOptionPane.WARNING_MESSAGE);
}

answered Aug 17 '15 at 11:24

additionster

628
4
14

sadia zar · Answer 2 · 2015-08-17T10:59:36.607

0

null ryan_assignment_sit2.CancelException: Please select a file at ryan_assignment_sit2.Person.loadcons(Person.java:105) at

Isn't it throwing an exception ? because you have passed the message to super class which is exception class.

you can try it just printing the warning using JOption pane instead?

edited Aug 17 '15 at 10:59

answered Aug 17 '15 at 10:54

sadia zar

62
1
8

so the message can't be shown using the exception ... sorry for lack of knowledge this is the first time doing this and I made this following a youtube video – Ryan Theuma Aug 17 '15 at 11:01
just try it may be it help :-) http://www.java2s.com/Tutorial/Java/0240__Swing/UsingJOptionPanetoDisplayaMessage.htm – sadia zar Aug 17 '15 at 11:02

Exception is not being captured

2 Answers2