Linux Mint Mate configure screensaver and display sleep via command line
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Posts by Year
2024
2023
ORA-17026: Numeric overflow when calling Oracle SQL function using Hibernate 6
A few days ago we stumbled upon a very strange error while migrating a legacy application from Spring Boot 2.7.0 with Spring Data JPA (Hibernate Core 5.6.9-F...
Kubernetes tail Spring Boot json logs in plain text Log4j (Logback) format using Stern
A few days ago we were debugging a Java Spring Boot web application (called engine-export-service) in Kubernetes and we wanted to tail the Pod logs. Since we...
2022
MS SQL Server Docker container restore database from .bak file created in Windows to a New Location
Yesterday, a client which uses Microsoft SQL Server 2008 R2 (SP2) wanted to test if his database backup can work in Microsoft SQL Server 2019 Developer versi...
SQL query to check if a date range is between two dates in Oracle database
A few days ago, we had to select records from an Oracle database table which should be inside a given date range. The difficult thing with those records was ...
2021
Go Mongodb Error Cannot create field X in element {Y: null}
Today we had a MongoDB 3.6 collection with the following documents:
Convert from/to JSON decimal fields in Go (golang) structs
Yesterday we had to marshal and umarshal to/from JSON some HTTP requests and responses in a Go microservice we are building. We already use ericlagergren/dec...
PostgreSQL case and accent insentitive SQL queries
A few days ago we were implementing a Spring Boot application which stored its data into a PostgreSQL database. As a requirement we needed to search into the...
2020
Convert Markdown to PDF using Docker, Pandoc and Asciidoctor
Today we had to deliver a .pdf file to a customer containing documentation about a system. The documentation was written in Markdown and needed to be convert...
2019
Force Maven to execute offline with local repository dependencies in a machine without Internet connection
Debugging an application which runs on a remote Virtual Machine can prove to be very hard, especially if your client has “exceptional” conditions due to secu...
MongoDB query to aggregate documents by a specific property
Yesterday a colleague had a problem on finding a query. His documents looked like the following:
2018
Solved: HP 630 notebook overheating problem
First Incident
Resolve “Could not find __debug_frame section in binary” when trying to Debug Metricbeat with Delve and Go 1.10.4
Today we were trying to debug Metricbeat (on commit #cff3e40c) using Visual Studio Code v1.27.2 and Delve debugger but it failed with the error:
Rsyslog - Parse Json and enrich IP with Geolocation using Maxmind GeoLite2 City and ISP
Today we wanted to parse some json logs which we had in a file using Rsyslog and enrich them with Geolocation information regarding the city and the ISP an ...
Logstash - Enrich IP with Geolocation using Maxmind GeoLite2 City and ISP
Today we wanted to parse some json logs which we had in a file using Logstash and enrich them with Geolocation information regarding the city and the ISP an...
Creating a Beat based on Metricbeat resolving Init and create metricset failures
I suspect that you are reading this post after having trouble creating a new Elastic Beat based on Metricbeat. Bud do not worry! We have you covered and solv...
Git merge conflicts using Tortoise Git merge in Windows
Today we wanted to use Tortoise Git Merge, a Windows Git utility which comes with Tortoise Git. It helps us do a 3 way merge and solve our conflicts easily. ...
Debug HTTP request of Java SOAP JAX-WS web service client
Today I wanted to debug in Java a JAX-WS SOAP web service client and see the exact message that is send as an HTTP request. So after searching, I found in th...
HTTP Basic Authentication in Java SOAP JAX-WS web service client
Today I had to create a Java client for a SOAP web service. So I opened Netbeans IDE and used the great tool which generates JAX-WS client code using the res...
2017
Install, configure and troubleshoot NTP servers in Debian Linux
If you are reading this article, perhaps you have searched a lot about NTP server installation in Linux, issues and problems encountered and how to troublesh...
MongoDB replica error RS102 too stale to catch up during full recovery
We run MongoDB 2.6.0 on a production system configured with a replica set of 3 members: Primary Secondary Arbiter
Use HAProxy and Docker to load balance requests to Solr and SolrCloud
We use Solr 4.6 with SolrCloud configuration in a production system. You may say: “It is hight time you upgraded to the latest version, isn’t it?”. And you w...
SublimeText 3 Fix greek (and other languages) accented chars input
Yesterday I installed SublimeText 3 editor (build 3143) in my PC and the first thing I realised was that I could not type any Greek accented characters. Thus...
Configure Eclipse in order to build MapStruct in Java projects
Today I was working on a Java Spring MVC project which uses Maven. My editor was the Eclipse IDE, with the current version of the M2E plug-in. When I pulled ...
2016
Let’s Encrypt SSL certificate without root or sudo privileges
Five days ago we had to renew a number of SSL certificates using free Let’s Encrypt SSL authority to a few Apache servers which were installed in Jelastic Pa...
2015
Migrate a Gitlab Docker container from version 8.0.4 to 8.2.0
Update 2016-05-13: The following procedure works perfectly for migrations from version 8.0.4 to 8.7.5
2014
JSON remove new lines via Linux and use it as string variable and as param in cURL POST request
Today I had to parse a JSON response in a JUnit test and then reuse it in a cURL command line call. Unfortunately I could not read the JSON response from a f...
Solr fix corrupted index using Lucene
A few days ago, a Solr server in our SolrCloud installation stopped unexpectedly. After examining solr.log file I spotted that it could not start again becau...
Linux: Extract audio and video using ffmpeg
Today I had some mp4 video files and I wanted to extract the audio and video into separate files. So to do that you can do the following:
Nginx https reverse proxy to Wordpress with Apache, http and different port
Today I had to hide a Wordpress 3.8.1 blog behind an Nginx reverse proxy configured to use only https. Nginx was behind an external firewall which forwarded ...
Export Untracked, modified, moved and deleted files from a Git repository to archive
Today I wanted to export to a .tar.gz archive all unstracked (new) , modified and deleted files from a Git repository. After some searching, I found a StackO...
Install Apache Solr as Windows Service using NSSM
Today I wanted to install Apache Solr index in Windows 7, Windows Server 2008R2 and Windows Server 2012 machines. So I achieved that , using the following st...
2013
Remove special and control characters from string using Python
Today I had a database table which contained special and control characters (like DLE, DC1, ACK, DC3 etc.) in its records. After some searching I found a way...
Read SMS directly from Sqlite database in Android
Today I wanted to extract the SMS content out of the android SMS application SQLite database using ADB.
Linux get hard disk statistics using Python
Today I wanted to collect disk usage information and send them to a remote server script. I used df command to collect disk usage information and Python to s...
Linux mount Windows shared directory via cifs and samba
Updates: 2013-08-08: Added sec=ntlm 2014-09-04: Added domain=mydomain parameter in order to connect to Active Directory domain
Fix Vmware tools “ kernel header path is not valid “ error
UPDATE (2015-05-13): Confirming that the following approach works for Lubuntu versions 12.10, 14.04 and 14.10 and Linux Mint 15 and 17.
Vi set color scheme , line numbers and syntax highlighting
Today I wanted to to set the Color Scheme in vi / vim in my Linux. The default configuration looks ugly:
MySQL connection ERROR 1129
Today I had to configure a MySQL database cluster and I faced the following error
Import a large sql dump file to a MySQL database from command line
Today I had to import a very large SQL dump file (6 Gb) to a MySQL database using windows command line. If you are using linux it is the same. The process is...
Install Raspbian Wheezy Linux to Raspberry Pi using Linux
Επιτέλους! (at last! in greek) After a month and a half of waiting, I received my Raspberry Pi! Now I am going to show you how to install Raspbian Wheezy Lin...
Change timezone to Apache server , PHP and MySql in XAMPP
I have installed XAMPP in my Windows machine and I want to alter the timezone in Apache HTTP server, PHP module and MySql in order to see proper dates in ser...
Java send smtp mail using Gmail
Today I wanted to make a mail notification mechanism for a project of mine. After some web searching I stumbled upon a mkyong.com tutorial where he uses SMTP...
2012
Java String Util Class
Unfortunately, Java does not include a proper String manipulation class in its Java SE SDK. I really do not understand why… However, we see so many implement...
Windows 7 64bit ODBC Data sources
Today I was trying to create and ODBC Data Source to a database using 32 bit database drivers. When I accessed ODBC Data Sources (32bit) from Control Panel, ...
Send email from VBScript using SMTP and Gmail
Today I wanted to send an email using SMTP from my gmail account. I searched the web and I found this and this and this which helped me a lot. So this is the...
PowerBuilder Datawindow Grid delete selected rows efficiently
Today I wanted to delete the selected rows of a datawindow grid in Powerbuilder. When I say delete I wanted just to remove them from the screen and not from ...
Perl UTF-8 and Regular Expressions
Today I wanted to explore Perl’s Unicode and regular expression capabilities, so I wrote down this simple script. It is quite amazing how simply Perl handles...
Java Calculate Orthodox Easter Date
Today I wondered if there is an algorithm to calculate the date of Orthodox Easter. After some searching in the web I found the algorithm and converted it to...
Ubuntu Debian Linux useful commands
Updated: 2015-09-08
Java get file size and download using HTTP
Today I wanted to download a file using Http protocol but before that determine its size. First aff all I open an Http connection and get file size using Con...
PowerBuilder 10 Get and Set System Language
Today I wanted to retrieve the selected system language from PowerBuilder 10. To accomplish that I had to do some search in the web. After a long period I fo...
SQL Server Select Table information
Today I am going to show you how do we obtain schema information in SQL Server 2005/2008. If you want to select all table names from a specific schema you ne...
SQL Server Truncate All Table Data
Today I want to truncate ( delete all table data) in a large SQL Server database instance. Plain delete statements are not going to work as there is a big nu...
Extend SQLiteOpenHelper as a singleton class in Android
Update: 2012-07-27
Launch Logcat programmatically in Android
Today I wanted to write logcat output to a file while my application is running. To do so I executed the following code:
Android pre-populated Database
Today I am going to show you how to create an android application which comes with a pre-populated database. The database file has to be stored in assets dir...
Bluetooth adapter device name and MAC address in Android
Today I am going to show you how to get the bluetooth adapter device name (if exists) and MAC address programmatically in Android. Note that this code will ...
Install Jboss 5.1.0.GA to Windows 7
Today I am going to show you how to install Jboss 5.1.0.GA on a Windows 7 machine.
Android Custom Dialogs Part 1: Set value
No Content Found
Check Network connectivity and obtain Wifi MAC address in Android
Updated: 2012-05-09
Android MD5 password encryption
Today I will show you how to generate the MD5 hash String for a given String in Android
Copy/Paste source code from Eclipse to Microsoft Word
Today I wanted to copy and paste a piece of code from Eclipse Indigo to Microsoft Word 2007 and keep the syntax highlighting. In some cases it worked but in ...
Android External Storage Free Space
Today I wanted to store some images to SD card and I wanted to find the available space:
Object ArrayList Sort
Let’s say we have a simple class called Person public class Person{ public String name; public int age; public Person(String name, int age) { this.nam...
Android get SQLite Library Version
```java /** * get the version of the SQLite Library that is installed in the android * system * * @return version , for example 3.5.2 */ public ...
Zip and UnZip in Java
```java package com.ots.pocketpolice.sync;
2011
Test1
Welcome to WordPress.com. After you read this, you should delete and write your own post, with a new title above. Or hit Add New on the left (of the admin da...