Java Thinking — Java and software development related thoughts

Default open action for Ubuntu

October 9, 2009

Something happened on my Ubuntu install sometime which meant that double clicking on an HTML file resulted in the file being opened by gedit. Not really what I wanted. I started looking through the GNOME system menu (Preferences and Administration) to find how to change the default action - but that turned out to be [...]

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The problem with Digital TV

August 21, 2009

The problem with Australian Digital TV or at least, using a media center in Australia is:

The standard def and high def channels are almost the same, but not quite. The high def channels have subtly different programs such as special documentaries.
The EIT is a mess - spelling mistakes, program name changes (series premire, [...]

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The week in review - 2009-32

August 19, 2009

SpringSource Roo
I just found out this week about SpringSource Roo - a rapid development tools that promises:
Working applications within 10 minutes of finishing the download
I haven’t used it yet, but at first glance it looks like a Grails/Rails type tool but being plain Java based as opposed to Groovy or Ruby based. This is a [...]

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Sharing data between applications

July 24, 2009

Sometimes applications need access to data from another application. Here is one approach you could take:

Define a view in the database that owns the data - this view should expose the data that the external application needs
Grant select permissions so that the external application can select from the view
Create a synonym in the external applications [...]

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Adding items to Gnome menus

July 10, 2009

I’ve always wondered how to add items to Gnome menus. Well, it turns out it is relatively easy - as you would expect - and its documented here.
It’s as simple as creating a text file in the right place - refreshing easy compared to the binary shortcuts in Windows.
When I was working on ToolInstaller, [...]

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No Scope registered for scope request

June 5, 2009

Recently I was working with some code which defined beans as request scope. Junit tests failed with the following exception while trying to initialize the application context:

Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: …; nested exception is java.lang.IllegalStateException: No Scope registered for scope ‘request’

I found the solution by searching around (unfortunately I didn’t record the [...]

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Trinidad and text wrapping

May 29, 2009

While using Trinidad 1.0.1 I came across a problem where text did not wrap when displaying read only text fields. This meant that everything was pushed off the right hand side of the page.
I had to change the fields from:

<tr:inputText label="#{msgs['message1']}" styleClass="labelRight"
[...]

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Virtual machines with VirtualBox

May 17, 2009

I’ve found VirtualBox to be very easy to create virtual machines - it’s free, open source, and available on Windows, Linux, Macintosh and OpenSolaris. One of the features I particularly like is being able to create a virtual disk that grows as needed (dynamically expanding image). You can also mount an iso image for the [...]

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Finding constraints in Oracle

May 13, 2009

It can be quite frustrating when you get exceptions like those below - constraint violations where the constraint has a system generated name which means nothing to you:

2009-03-23 23:30:43 ERROR [AbstractFlushingEventListener.performExecutions] Could not synchronize database state with session
org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update
…
Caused by: java.sql.BatchUpdateException: ORA-00001: unique constraint (SAMPLE.SYS_C00123456) violated
…

The easiest way to find [...]

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