James Gordon

Hi,

It was well documented that the draw back for DefaultAuditStrategy is that the queries of audit information uses sub-queries,
which is slow. I'm not able to comprehend on the need of the sub-queries. Why do we need it at the first place?
For example, if we would want to find revision 10 through the statement below, isn't retrieving with REV = 10 already sufficient.
 AuditReaderFactory.get(session).find(MyObject.class, id, 10);
Why is there a need for the sub-query:
 select *  from mytab  where mytab.REV=(    select max(subtab.REV)    from subtab    where subtab.REV<=10) and mytab.REVTYPE<>2
Please enlighten me on this.

Thanks.

Hi,

I've two Wildfly servers, one under Windows OS and another under Linux.
I'm curious as to why we have to bind the IP address during start up in Linux
environment, but it's not needed in Windows.

./standalone.sh -b=0.0.0.0

If the above is not done in Linux, the deployed application would not be accessible
by a remote browser.

Can anyone please shed some light on this.

Thanks.

The id is reflecting the class signatures.
Adding field, methods or changing types means by right it should be updated.

In my opinion, it's quite reasonable for anyone to miss it.

Or given another circumstances, if we're to take over the piece of source codes,
how can we be sure that the id were well maintained previously.

Anyhow, noted, no easy way to verify.
But the good news is most likely it won't affect much anyway ...

Thanks.

Hi,

Due to copy and pasting during development, some of the serialVersionUID might not be correct,
as the developer might forgot to re-generate them.

As such, is there any easy way to scan and verify through the correctness of a bunch
of java class files?


Thanks.

Regards.

Hi,

I'm just wondering, if a socket server is writing a mixture of int, short, text, etc
(DataOutputStream: writeInt, writeShort, writeBytes)
to a client, is there anyway for the client to determine the data type
so that the message can be constructed back properly.

Sample code:
out.writeShort(20); out.writeBytes("Hello World"); out.writeInt(1000);

ie: From the client perspective, are we able to determine that
the 1st piece of data is short, 2nd a string and 3rd is an integer?

Of course, an alternative is to have a fixed format.


Thanks.

Dear Paul,

The target email address is definitely valid and I've been using it for the past 10 years.
As mentioned, Outlook Express managed to send it out.

Hi,

My java mail code doesn't seem to be able to send out to external email addresses.
It only work for internal email addresses.
I'd set the authentication though.

To verify that it's code issue, I tried with Outlook Express instead.
I provide the same exact account information and authentication for outgoing mail.
It works with the mail client.

I'd reviewed my code few times but didn't see anything wrong.
Could someone please point out if there's any issues with my code.


Thanks in advance.



public static void main(String[] args) { Properties p = new Properties(); p.put("mail.smtp.host", "192.1.1.31"); p.put("mail.smtp.port", "25"); p.put("mail.smtp.auth", "true"); String u = "sender@xxx.com"; String pw = "password"; p.put("mail.smtp.username", u); p.put("mail.smtp.password", pw); Session s = Session.getInstance(p, new Authenticator(u, pw)); s.setDebug(true); MimeMessage m = new MimeMessage(s); try { m.setFrom(new InternetAddress(u)); InternetAddress[] a = new InternetAddress[] { new InternetAddress("recipient@yyy.com") }; m.addRecipients(Message.RecipientType.TO, a); m.setSubject("My Subject"); m.setText("My Content"); Transport.send(m); } catch (Exception ex) { ex.printStackTrace(); } } private static class Authenticator extends javax.mail.Authenticator { private PasswordAuthentication auth; private String user; private String pwd; Authenticator(String u, String p) { this.user = u; this.pwd = p; } protected PasswordAuthentication getPasswordAuthentication() { if (auth == null) { auth = new PasswordAuthentication(user, pwd); } return auth; } }

DEBUG: setDebug: JavaMail version 1.3.1
DEBUG: getProvider() returning javax.mail.Provider[TRANSPORT,smtp,com.sun.mail.smtp.SMTPTransport,Sun Microsystems, Inc]
DEBUG SMTP: useEhlo true, useAuth true
DEBUG SMTP: useEhlo true, useAuth true
DEBUG SMTP: trying to connect to host "192.1.1.31", port 25

220 RALD.xxx.com Microsoft ESMTP MAIL Service ready at Tue, 11 Sep 2012 15:16:38 +0800
DEBUG SMTP: connected to host "192.1.1.31", port: 25

EHLO ROY
250-RALD.xxx.com Hello [192.1.1.20]
250-SIZE
250-PIPELINING
250-DSN
250-ENHANCEDSTATUSCODES
250-STARTTLS
250-X-ANONYMOUSTLS
250-AUTH NTLM
250-X-EXPS GSSAPI NTLM
250-8BITMIME
250-BINARYMIME
250-CHUNKING
250-XEXCH50
250-XRDST
250 XSHADOW
DEBUG SMTP: Found extension "SIZE", arg ""
DEBUG SMTP: Found extension "PIPELINING", arg ""
DEBUG SMTP: Found extension "DSN", arg ""
DEBUG SMTP: Found extension "ENHANCEDSTATUSCODES", arg ""
DEBUG SMTP: Found extension "STARTTLS", arg ""
DEBUG SMTP: Found extension "X-ANONYMOUSTLS", arg ""
DEBUG SMTP: Found extension "AUTH", arg "NTLM"
DEBUG SMTP: Found extension "X-EXPS", arg "GSSAPI NTLM"
DEBUG SMTP: Found extension "8BITMIME", arg ""
DEBUG SMTP: Found extension "BINARYMIME", arg ""
DEBUG SMTP: Found extension "CHUNKING", arg ""
DEBUG SMTP: Found extension "XEXCH50", arg ""
DEBUG SMTP: Found extension "XRDST", arg ""
DEBUG SMTP: Found extension "XSHADOW", arg ""
DEBUG SMTP: Attempt to authenticate
DEBUG SMTP: use8bit false
MAIL FROM:<admin@xxx.com>
250 2.1.0 Sender OK
RCPT TO:<recipient@yyy.com>
550 5.7.1 Unable to relay
DEBUG SMTP: Invalid Addresses
DEBUG SMTP: sender@xxx.com
DEBUG SMTP: Sending failed because of invalid destination addresses
RSET
250 2.0.0 Resetting
QUIT

Dear Sunil,

The problem is fixed after I removed this element from the jnlp file:
<update check="background"/>

The versioning approach you suggested is working as well.


Thanks for the advise.

Hi,

I'm trying out the Web Start auto loading new application feature.
After putting in a new jar file in my web server, it still load the old version unless
I remove off the application at the Java Cache Viewer. I'd even waited
for 30min incase it only load after certain interval.

I'm using this sample application.
http://download.oracle.com/javase/tutorial/deployment/webstart/examplesIndex.html#DynamicTreeDemo

I just change some labels to make it a new version.

Is this behaviour expected because from what i read, Web Start should be
able to detect and load new version. Or is there any configurations that I need to do?



Please advise.


Thanks in advance.

Hi,

Old codes always run on newer JEE server.
That's good but I'm just wondering whether there's any impact
in terms of efficiency, performance, etc.

I thought of few scenarios:

1) old codes (v1.3), old compiler/binaries (v1.3)
2) old codes (v1.3), new compiler/binaries (v1.5)
3) new codes (v1.5), new compiler/binaries (v1.5)

* old codes meaning codes written with old syntax
* old compiler/binaries meaning classes generated with old jdk
* version number provided is just example


Any comments?


Thanks.

Thanks Maneesh. That solved my problem.

Hi Darryl,

By removing the JLabel, I'll end up with blank lines.
Consequently, I would still have to refresh the JDialog right?

item 1
<blank line>
item 3

That's what I'm trying to figure out - how to refresh the screen.


Thanks.

Hi Pete,

Using JList and JTable is a good way around but then the effect
of the display is going to be different.

What's in my mind is to have the whole panel scrollable instead
of scrolling within the JList/JTable.


Thanks.

Hi Rob,

I used snippets intentionally as I felt this is more of a concept issue.
SSCCE might be too much to be swallowed

Anyway, below is the SSCCE.
My objective is to get the JDialog to refresh to reflect the
deleted PO item after the delete button is clicked.

I managed to achieve it by disposing and re-creating the JDialog
but there might be better ways.


import java.awt.BorderLayout; import java.awt.GridLayout; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.util.ArrayList; import java.util.List; import javax.swing.JButton; import javax.swing.JDialog; import javax.swing.JLabel; import javax.swing.JPanel; public class MyDialog extends JDialog implements ActionListener { private JPanel pane = new JPanel(new GridLayout(0, 2)); private JButton button = new JButton("Delete"); private List lineItems; public MyDialog() { paintDialog(); } private List getPOItems() { List items = new ArrayList(); items.add(new POItem(1, "Item 1")); items.add(new POItem(2, "Item 2")); items.add(new POItem(3, "Item 3")); return items; } // Add all the UI components private void paintDialog() { setLayout(new BorderLayout()); lineItems = getPOItems(); for (int i = 0; i < lineItems.size(); i++) { POItem item = (POItem) lineItems.get(i); JLabel itemNo = new JLabel(String.valueOf(i + 1)); pane.add(itemNo); JLabel desc = new JLabel(item.getDescription()); pane.add(desc); } add(pane, BorderLayout.CENTER); add(button, BorderLayout.PAGE_END); button.addActionListener(this); setSize(200, 200); setVisible(true); } // Remove item from value object and refresh to reflect deleted item private void removeLineItem(int idx) { lineItems.remove(idx); // Trying to refresh the JDialog pane.validate(); pane.repaint(); } public static void main(String[] args) { MyDialog d = new MyDialog(); } public void actionPerformed(ActionEvent arg0) { removeLineItem(1); } } class POItem { private int itemNo; private String description; public POItem(int itemNo, String description) { this.itemNo = itemNo; this.description = description; } public int getItemNo() { return itemNo; } public void setItemNo(int itemNo) { this.itemNo = itemNo; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; } }

Hi,

I've a JPanel added to a JScrollPane.
In the JPanel, I added a lot of JLabel/JTextField
on purpose to make sure that scrollbars appear.

The scrollbars came out but I ended up with
cramped JLabel/JTextField instead.

This is a link to how it looks like:
http://www.imagebam.com/image/b69f6375343718


Below is my code:

public class ScrollJPanelTest extends JFrame{ public ScrollJPanelTest (String title){ super(title); setDefaultCloseOperation(EXIT_ON_CLOSE); MyPanel p = new MyPanel(); JScrollPane jsp = new JScrollPane(p); getContentPane().add(jsp); setSize(300, 300); setVisible(true); } public static void main (String [] args){ new ScrollJPanelTest("Scrolling Jpanel"); } } class MyPanel extends JPanel{ public Dimension getMinimumSize(){ return getPreferredSize(); } public Dimension getPreferredSize (){ return new Dimension(300, 300); } public MyPanel() { setLayout(new GridLayout(0, 1)); for (int i = 0; i < 20; i++) { add(new JLabel("Text " + i)); add(new JTextField("Text " + i)); } } }

Could anyone please advise what's wrong with my code.

Thanks.