Errors occurred during the build – java.lang.NullPointerException

I was trying to make a project clean today and started receiving this error. The “solution” to this as it doesn’t really give you any insight is to disable the Javascript Validator from Project -> Properties -> Builder.

In my case it solved the problem for one of the projects I had in my workspace, but I was still getting it in another project. What I did was to go the project that had been solved and copied the file “org.eclipse.wst.jsdt.core.javascriptValidator.launch” from the folder “.externalToolBuilders” to the other project that still had the issue and that did the trick.



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Remove blocked IPs caused by mod_security at Linux servers

It is quite common a client or even myself not being able to access my website. This is caused because mistakenly the mod_security (a module installed at linux servers to secure your website against malicious users) has placed the IP address at the deny list after thinking it is a suspicious IP. The way to remove it and have access to your site again is:

1) Locate the file: /etc/apf/deny_hosts.rules

2) Remove your IP

3) Restart apf: apf –restart

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ecoBlueberries presented at the greek magazine Real Taste and Style

A lot of activity has happened recently at ecoBlueberries. The wiki has almost been completed with information regarding the blueberries cultivation while the forum got some activity as well. The search engine optimization campaign both on-site and off-site has come to an end giving me a percentage of 82% of all visitors coming from organic searches while has over tripled the traffic during the last 4 months.

Recently I was interviewed by the magazine Real Taste and Style, a magazine specialized at issues around food and presents people that keep the food traditions of Greece or have innovative ideas.

Here you can see the interview as it was presented by the magazine which was distributed along with the newspaper Real News (the interview is in greek):

Presentation of ecoBlueberries on 10th of June at the monthly magazine Real Taste & Style which comes with the Sunday newspaper Real News.

Link with higher resolution:

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Prestashop: All modules cannot be loaded due to memory limit restriction reason

Prestashop version:

Problem: All modules cannot be loaded due to memory limit restriction reason, please increase your memory_limit value on your server configuration

Solution: At /config/ add:


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How creativity works

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PHP Bug with DateTime diff

After PHP 5.3.0 DateTime::diff was introduced to help with the comparison between two DateTime objects. However it still seems to be a bit buggy. While I was developing a statistics tool and trying to group occurrences by month, I got into a problem with diff functionality between February and March. If you try the following code you can probably reproduce it. (More info and a temporary solution is provided at the 2nd comment)
Continue reading

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Dropbox lied about encryption, it is not really safe

Christopher Soghoian recently uncovered the lie behind Dropbox. Dropbox was claiming that the files are encrypted (those that are not publicly available) and noone could have access to the files.

However certain employees of dropbox could have access to your files if needed (forced by law, or whatever) which means that your files were not really encrypted or that your key was available to them as well, so they could decrypt it. Moreover because of the deduplication process (only one instance of a certain file is uploaded at the server) which was for all files throughout the servers, people could try to upload a specific file and check if it is already uploaded if there was no real upload made.

An alternative to dropbox is spideroak which I just downloaded. It claims that no one can access the files except you, if you lose your password you lose your files. The deduplication process occurs only within your account and not server wide.

More info about dropbox:

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TKOC is now open source / free software

The Kingdoms of Chaos is now open source / free software. Everyone can modify it and contribute to improve the game.

The Kingdoms of Chaos is an online strategy game. You compete with several other players from all over the world to create the most powerful province and kingdom.

Our idea of the game is to be totally community based which means that an ecosystem would be built around it that will develop and maintain the game.

If you are interested to participate:
- You can find the code online:
- Installation guide is available at the wiki:
- A short guide on how to use Git:

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Add right side widget to beauty dots theme for wordpress

The theme beauty dots comes with only one widget support at the footer section of the page. In order to solve this and provide support for the right side area as well, we need to investigate of where the problem occurs.

First we check the file sidebar.php, where we see:

if ( ! dynamic_sidebar( 'sidebar-widget-area' ) ) 

which means that the theme expects a dynamic sidebar, but for some reason it doesn’t show up. The next step is to check the file functions.php and there we see:

register_sidebar( array(
		'name' => __( 'Footer Widget Area' ),
		'id' => 'footer-widget-area',
		'description' => __( 'The footer widget area' ),
		'before_widget' => '',
		'after_widget' => '',
		'before_title' => '',
		'after_title' => '',
	) );

The ‘sidebar-widget-area’ is not mentioned anywhere in the file, so what is needed is to register the ‘sidebar-widget-area’ as well. So just above of the previous function we add:

register_sidebar( array(
		'name' => __( 'Right Widget Area' ),
		'id' => 'sidebar-widget-area',
		'description' => __( 'The right widget area' ),
		'before_widget' => '',
		'after_widget' => '',
		'before_title' => '',
		'after_title' => '',
	) );

Now go at your widget menu and there you will see the right widget, where you can customize it.

Keep in mind that if you want to change the id, you have to do that in both files: sidebar.php and functions.php

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Compare Scrum and Kanban

Here is a very good reading and presentation of those two agile methods:

“There’s a lot of buzz on Kanban right now in the agile software development community. Since Scrum has become quite mainstream now, a common question is “so what is Kanban, and how does it compare to Scrum?” Where do they complement each other? Are there any potential conflicts?”

Continue reading Kanban vs Scrum

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