Learning Java

Before attempting to encode a link to MySQL, I thought I'd install MySQL on my local machine and have a bit of a play. My first port of call was the home page of the MySQL web site. I couldn't see any obvious link to installation or user instructions, so I tried the Windows page , but again it was all about selling the produce rather than using it. So I did a How to search on Google and ended up on a wikihow page which fitted the bill. The screenshots on the installation page were from version 4.1 (I was installing 5.5), but they still pretty close to the mark. The recommendation to select "Standard Installation" from the Server Instance Configuration Wizard was a bad one because it hung. The default selection for custom installation worked better, not least because it automated the addition of the correct port to the Windows firewall. Another reason the installation hung on my machine was AVG blocking the wizard, and it was not immediately obvio...

So I have started a blog for my Rasch Itembank Project , and the address is: http://rasch-itembank.blogspot.com The Learning Java blog will now be kept for java related issues, including issues related to data storage and access. I am currently using a Derby database, and I had a few teething problems with that. Anyway after failing to find an ISP who would host a derby server for me, I have now found one who will host MySQL. So that will be a new learning curve for me.

This blog was created to record my journey in learning Java. While that journey might not have completely reached its conclusion, it has certainly started to plateau. I posted 22 pages in the last four months of 2008, 66 in 2009, and just 11 in the whole of 2010. Most of my 2010 posts related to my psychometric project , which is another journey really, and I think is worthy of its own blog. If people run a search on "learning java" they probably won't be very interested in the ups and downs of my math project, but if they run a search on "Rasch" or "Scoring Rates", I'd like them to find me writing a blog focused on the topic, rather than rambling about the ins and outs of Java. I shall post a link to the new blog here when it begins (which might not be until some time in 2011), and keep any new posts in this blog more closely related to learning new tricks in java.

The code currently uploaded to my java project at covers only the front end of the application. I have not formalized the back end. It remains a collection of code scraps, which I use from time to time to check what is in the database, or less often to change what is in the database. I have not formalized it because I am currently the only user. In previous incarnations of the app I have incorporated data queries, with all sorts of filters and user customization, which no one has understood how to use. My current ad hoc query code is as follows: public class ItemdbQuery { public static void main(String args[]) throws ClassNotFoundException, SQLException { /** * These are shared variable declarations */ Connection connect = null; Statement stat = null; /** * This is the start of the main code. */ System.out.println("try connection"); try { // Load database driver Class.forName("org.apache.derby.jdbc.ClientDriver"); // Make connection String connn = ...

It is embarrassing, whatever ones business, if a client rings up for an appointment, and you have to keep them waiting for 30 or more seconds while MS Outlook cranks into action. It is especially embarrassing if the client is calling to ask you to build a new computer for them, which they hope will be quick and easy to use. My old excuse was that I was using a Dell Pentium III laptop, which for sentimental reasons I didn't have the heart to throw out. But I am now using a recently built system using a Pentium Core 2 Duo processor and 2 GB RAM to run Windows XP pro. So what is my excuse now? When I built the system I partitioned the hard drive and put an identical OS on both partitions. The idea was that the C drive would be my top copy, and the D drive would be for experimentation. But I was so paranoid about intalling anything on the C drive, the D drive became my de-facto working drive. And it is the D drive on which MS Outlook displays the flash screen for 30 ...

When I first began this blog , I was pretty down on the official Java Tutorial on the Sun website . I was especially down on the Java Tutorial trail JDBC(TM) Database Access , which describes how to make a connection with a database. But a year later, I find myself scanning my own blog, which I thought comprised the finest pearls of clarity and wisdom, and I can't find any description, let alone a better description, of how to connect to a database without using a GUI app like NetBeans. There is an entry, entitled " Building a financial mini-app ", which describes an application of such a connection, but it is distinctly unhelpful to anyone wanting to build such a tool for themselves. Indeed I found it distinctly unhelpful even to me, trying to re-apply my own code. I shall therefore attempt to re-write the page in a slightly less cryptic fashion. This has nothing to do with my Rasch-Itembank project at java.net, but for me it is a useful exercise ...

The idea of my Rasch-Itembank open-source project at java.net is to produce a large numeracy estimation item bank, which updates the estimated difficulty parameters in real time, as it is used. To work properly, the client needs to generate items from the item bank according to the latest item difficulty estimation. The most reliable current working version of my Java Math Test client is a complete cheat. It has absolutely no connection with a database, it is ISP hosted, and it usually works first time, as long as the user has the JRE installed. A second version, hosted by me , is a partial cheat. It connects to a database to record performance data, but it uses hard coded arrays of items, whose difficulty has been estimated from static data collected in the past. This version is less reliable for many reasons. I don't always have the server turned on, I don't always have the database turned on, and sometimes my IP address changes. The conundrum is that to...