org.hibernate.LazyInitializationException

 I had configured the OpenSessionInViewFilter as expected and yet I was still encountering this error.
After much debugging and code tracing in hibernate and in spring, it boiled down to the spring class

SessionFactoryUtils requiring the the sessionFactory instance be the same in the DAOs and in the filter.
After dumping out the identity of the session factories using System.identityHashCode() method, I discovered that they were in fact different instances hence the:

"no session or session closed" error message!

Why do I have multiple session factories?
It's because in the web.xml and the spring XML configuration it was read twice!

See the following link for more details

http://forum.springsource.org/showthread.php?t=85782

Once I reconfigured spring to only load each configuration file only once, the error message went away!

ThreadLocal is cool

http://javaboutique.internet.com/tutorials/localdata/

Windows 7 Wireless Crash

According to Microsoft:

“This issue tends to occur when you select a Wireless LAN from 5 or more access points. (…) This problem occurs because the message handling for Wireless connection is not fast enough and causes overflow in the message queue,”


Here is the official bug report on Microsoft's website:
http://support.microsoft.com/kb/979244/

However, they don't mention any realy solutions, other than to move your computer away from too many wireless access points. Not a real solution at all.

One user reported in detail the pain he went through and the solution he used to get it working:
http://blogs.techrepublic.com.com/window-on-windows/?p=2342

The solution?
Disable IPv6

Lazy Loading with Java's InvocationHandler

To make the most of performance, we typically don't want to eagerly load everything on a DAO Transfer object. We can use Java's InvocationHandler to proxy method calls. Here's a good read on how to do it:

http://blog.frankel.ch/the-power-of-proxies-in-java

Good tutorial on CSS positioning

http://www.barelyfitz.com/screencast/html-training/css/positioning/

AJAX and accessing DIV elements

In Firefox I encountered a strange problem when using AJAX to access DIV elements.
I was using a timer to repetitively access a DIV element as follows:

Javascript:

var statusEl = document.getElementById('status');
alert('statusEl'+statusEl);

HTML:

<div id="status" />

On the first timed interval, firefox has no problem finding the element and the alert identifies it as an HTMLElement object. But upon subsequent timed intervals, the alert begins to report the statusEl as null!! Very strange indeed.

Solution:

The solution ended up being to change from <div id="status" />
to <div id="status"></div>

Differentiating objects in Java

Use System.identityHashCode(obj) to differentiate objects in java