Filling in the Gaps

Convert PNG to JPG

Admin — Wed, 29 Jun 2011 10:30:34 +0000

Needed to do this quickly and found a neat utility – Convert png to jpg.

Java MidiSystem on Windows – No Sound

Admin — Thu, 11 Jun 2009 16:53:40 +0000

If you’re not getting any sounds from Java’s javax.sound.midi package on windows, you might just need a soundbank. You can download one here: http://java.sun.com/products/java-media/sound/soundbanks.html

Place the .gm file on the classpath, e.g. next to the JAR you’re running and you should have sound.

Stop maven downloading poms

Admin — Sun, 03 May 2009 11:56:39 +0000

Maven often seems like it’s trying to download the entire internet when all you want to do is a simple rebuild. This is slow! You can stop it doing this by running in offline mode with “-0″ e.g.
mvn package -o

Java Puzzler – Super must be first line in constructor

Admin — Wed, 04 Mar 2009 21:31:38 +0000

Why do you get a compiler error about super() needing to be the first line in a constructor with this code?
public class Foo { public void Foo() { super(); } }

answer after the jump…

public void Foo() isn’t a constructor, it’s a method, since constructors don’t have a return type – the error message is a little misleading!

Getting the color of a pixel in an image in JavaScript

Admin — Sat, 24 Jan 2009 09:58:48 +0000

This is far from cross browser as it requires HTML 5 Canvas support, but might be fine for environments where you can target just supporting browsers. Note that the same origin policy means you can only use this on images from the same domain as the javascript – you can’t just point it at any image url. So here’s a basic example that will give you the RGB value for a pixel in an image.




References:
http://www.whatwg.org/specs/web-apps/current-work/#dom-context-2d-getimagedata



How to get the current controller or action in Grails
Admin — Sat, 17 Jan 2009 17:12:46 +0000
The current controller, action and id are available in params.  So this is as simple as ${params.controller} or ${params.action} in a view for example.  There is an open issue to make this easier, but it probably just needs better docs rather than a shortcut.

         


Passing Xmx to JUnit with Maven
Admin — Thu, 15 Jan 2009 20:34:17 +0000
If your tests are running out of memory when they run via Maven you can pass through the relevant JVM args, likely just -Xmx, in the pom, like this:





org.apache.maven.plugins

maven-surefire-plugin



-Xmx512m







         


MySQL errno 121
Admin — Fri, 09 Jan 2009 22:15:47 +0000
It’s not immediately obvious why you’d run into this when running CREATE TABLE – but it’s likely to be having foreign keys/constraints with the same name.  The constraint names need to be unique across the database.

         


Grails jobs
Admin — Wed, 07 Jan 2009 22:49:17 +0000
Grails has plenty of success stories, and is getting use on sites from sky movies to mashups to party dresses.  The job market for Grails is still in its infancy though – just 27 job ads in the last 3 months in the whole of the UK.    Coming under the Spring Source umbrella will help so it’s worth keeping an eye on that chart.
Is it going to kick off like rails?

         


How to show  SQL queries in Grails
Admin — Fri, 02 Jan 2009 20:39:04 +0000
If you want to see the actual SQL queries Grails is using (via Hibernate) you can configure this in DataSource.groovy.  Just add

loggingSql = true  along with the driver and URL.