Github as maven repository
We can use github as personal maven repository so that we can share code/lib among other projects
Friday, July 26, 2013
Wednesday, July 10, 2013
Singleton pattern in java
July 10, 2013 Suraj Chhetry
Although Singletons are not encouraged because it can make it difficult to test it's clients, we can create it in three ways.
- With Public final filed
- With Static Factory
- With Enum
Saturday, July 6, 2013
maven spring JPA configuration on google app engine
July 06, 2013 Suraj Chhetry
From few days I was trying to configure my first app on google app engine(gae) with maven but due to some incompatible version of datanucleus and gae , I was not able to run the application.After spending few couple of days I have finally configured spring ( DI,mvc and Security ) and JPA with maven.I am sharing my configuration so that it will be beneficial for someone.
Monday, July 1, 2013
Object Oriented Software Development with Java
July 01, 2013 Suraj Chhetry
Object Oriented technologies are a popular paradigm for developing applications. This approach models an application around a series of real world objects, such as an employee or a ship. In order to solve a problem, it is useful to think of the real world objects that make up the problem domain.
The OO approach is based on three distinct activities:
The OO approach is based on three distinct activities:
- Object Oriented Analysis (OOA): This is concerned with determining the functionality of the system, that is, what should the application do
- Object Oriented Design (OOD): This is concerned with how the architecture supports the functionality of the application
- Object Oriented Programming (OOP): This is concerned with the actual implementation of the application
Sunday, June 9, 2013
Communicating with serial port
June 09, 2013 Suraj Chhetry
These days I am working on embedded ARM linux devices. I am writing an application for it. I was using Hyper terminal( windows machine ) to transfer image file,even though I am using linux for development( coding ).This suggestion was given from the vendor and since it is my first project in embedded , I am doing whatever they are suggesting. Just for file transfer I have to use windows machine which was giving me bad feeling .So this morning I decided to setup serial port with linux and will try to transfer file by linux.I have tried a lot of tools like minicom,cutecome,gtkterm and c-kermit . After trying around 2 hours I am able to transfer file from linux to POS machine using serial port with the help of kermit. So , I decide to write the procedure of it for future reference.
Useful resources for writting your own operating system
June 09, 2013 Suraj Chhetry
Here are some useful resource link to write your own operating system.
- http://himmele.blogspot.com/2011/07/build-your-own-operating-system.html
Installing Oracle java in linux
June 09, 2013 Suraj Chhetry
Open JDK comes with linux as default Java provider.In order to install Oracle java here are some step
- Download oracle java from here
- Select Java Platform (JDK)
- Accept License Agreement
- Download by Clicking on *-linux-x64.tar.gz( for 64 bit OS ) or *-linux-i586.tar.gz( for 32 bit OS )
- make a folder anywhere you want to keep java ( recommended on /opt) by using
sudo mkdir /opt/java - give full permission to this folder by
sudo chmod 777 -R /opt/java - unzip downloaded file on /opt/java
- open .bashrc for editing
- append following lines at the end of file and save it
export JAVA_HOME=/opt/java
PATH=$JAVA_HOME/bin:$PATH
10. Open terminal and type
source .bashrc
11. Open terminal and perform below command to make sure java is installed properly
java -version
if above command successfully executed ,congratulation java is installed.Otherwise please check above step properly.
Daily Useful Linux Command
June 09, 2013 Suraj Chhetry
Daily Useful Linux Command
- rm -rf FOLDER_NAME - To Delete Folder and it’s contain
- df -h - To View available disk space
- gunzip -c foo.tar.gz | tar xvf - To unzip
- tail -f FILE_NAME.log - To monitor log file
- ps -af - To display all the processes running on the host
- uname -r - To print Linux version information
- more /proc/cpuinfo - To print hardware summary
- history - To Call commands from History
- !23 ( where, 23 history id ) - To Call commands from History
Some basic linux information
June 09, 2013 Suraj Chhetry
Useful Files
- /boot/vmlinuz – the typical location and name of the Linux kernel. In the Slackware distribution, the kernel is located at /vmlinuz.
- /dev/fd0 – first floppy disk drive
- /dev/fd0H1440 – driver for the first floppy drive in high density mode. Generally, this is invoked when formatting a floppy drive for a particular density. Slackware comes with drivers that allow for formatting a 3.5″ diskette with up to 1.7 MB of space. Red Hat and Mandrake do not contain these device driver files by default.
- /dev/fd1 – second floppy disk drive
- /dev/hda – first IDE hard drive
- /dev/hdc – on many machines, the IDE cdrom drive. Most often, there is a symbolic link called /dev/cdrom which is just a link to the true cdrom driver file.
- /dev/null – used when you want to send output into oblivion
- /etc/aliases – file containing aliases used by sendmail and other MTAs (mail transport agents). After updating this file, it is necessary to run the new aliases utility for the changes to be passed to sendmail.
Saturday, June 8, 2013
Clean Code Cheat Sheet
June 08, 2013 Suraj Chhetry
Download Clean Code Cheat Sheet provided from here
Thursday, March 14, 2013
Running java application as linux daemon
March 14, 2013 Suraj Chhetry
Linux daemon is a application which runs as a background process,rather than being under the direct control of an interactive user.We can create a java application that can run as daemon process. Here is few step which will help to create a linux daemon process.
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