Ctrl + Space in Windows 7

I have upgraded OS. Now I have Windows 7 (with more then one system language set up).
So after installation of Eclipse I was faced with a problem of not working shortcut CTRL+SPACE.

This shortcut is used by Windows7 to change system language.

I have found a webpage with description how to fix it:
http://www.mkyong.com/java/content-assist-ctrl-space-is-not-working-eclipse/

Now it works!

Changes to Java certificates. Not August 1, but September 30

Those who plan to make Java certificates, especially Java Developer and Java Architect, must know that Oracle changed requirements for them this year. From 1st August three expensive trainings will be required.

But I have read today, that deadline was postponed to September 30.

So changes apply to following certificates:
Java Architect, Java Developer, Solaris System Administrator and Solaris Security Administrator
Details on:
http://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=449

Astah for UML

I have recently needed a tool to generate UML diagram. It's been ages since I was using one. I think that was during my studies. As far as I can remember I was using ArgoUML. By the way, today it is not often used in the project as it used to be. Probably because of Agile approach.

I have found that ArgoUML hasn't had any new releases for a few years.
However, I found Astah. It is quite a useful tool.
http://astah.change-vision.com/en/index.html

The community version is free.

So if you need to build UML diagrams, I can recommend it.

Problem with preferredMapping in Spring roo

I wish to present next error I have faced during using roo as a development tool.

In command controller class I used attribute --preferredMapping createSimple
So attribute consist capital letter, it cannot have as a value with capital letter.

In generated controller mappings on controller and to view names was not correct. In html it was generated lower case, but in mapping was with a capital ones. I have to fix them by had for it running.

Problem with roo + gwt

I have upgraded Spring roo to the version 1.1.4

It ended with the problem using gwt web frontend, with an error:

GWT module's gwt.xml file not found; cannot continue

I have found the cause: https://jira.springsource.org/browse/ROO-2445

So in Spring roo ver. 1.1.4 generating gwt web is not working

Referer

We do use HTTP Headers in coding web pages for the information from the browser client use.
f.e. I used Referer header to know which from which page new request comes.

I have discovered that it is not always true. On Firefox it was, but on Chrome and IE when the link was clicked in the Flash object Referer was set to the address of that flash object.

So be careful, Referer can be
- url of the page on which link was clicked,
- url for the flash object on which link was clicked.

Principles of object-oriented design

SOLID - five simple principles of object-oriented design
introduced by Robert C. Martin

- Single responsibility principle (S) - that an object should have only a single responsibility
- Open/closed principle (O) - “software entities … should be open for extension, but closed for modification
- Liskov substitution principle (L) - objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program
- Interface separation (I) - many client specific interfaces are better than one general purpose interface.
Dependency inversion principle (D) - Depend upon Abstractions. Do not depend upon concretions.