Ramki Technical Blog

In this post  is  a continuation of Jasper Report Part 1 . here we will discuss about some advanced jasper report concepts like passing complex object like List, Date object and how to create and use local variable in jasper report, Add the sub-report and background image to report. Check my latest post about  Integrate Charts into Jasper Reports . here i am using JPA (Java Persistence API) for accessing the Database. so i create the two entity ShoppingCart and Item. here ShoppingCart entity contain list of Item entities. then i am going to pass these objects to Jasper Report. (Check the video in below) ShoppingCart.java Item.java Create Report           now i am going create report. we can use iReport standalone or iReport Netbeans Plugin to create the report. first we need to create some fields in report. these fields are matched with ShoppingCart Bean property names and Data types also. and set the data types of these fields correctly. firstName  ==>

In this post we will see how ssh works?, what is SSH tunneling? what is important of ssh tunnels and how to setup the ssh tunnel. When SSH server is installed in machine then by default its allowed ssh tunneling. SSH Tunneling (Port Forwarding) Tunneling is the concept to encapsulate the network protocol to another protocol. here we put into SSH. so all network communication are encrypted. It also called Port Forwarding. because in ssh tunneling we are going to bind one local port. so what are the packet we are going to send that particular port, all packets are transparently encrypt and delivered to remote system. What is the need for SSH Tunneling?      SSH is enough to administrate the remote system. its not enough to access the all services which are available in remote system. let i describe in the following scenario, now lets consider the scenario, System (192.168.56.101) is my system its connected to internet and server its called PrivateServer (192.1

Recently I compiled the latest kernel by manually for just fun. so i logged my experience here. I show the step by step to the compilation process. I followed the this reference for compile the kernel. Why Need to compile the Kernel? Some time some software or modules expected that some kernel flags needed to set while compile (build) the kernel. This kind of scenario we need to rebuild the kernel with specified configuration flags are set. When new kernel is released,  compile the new kernel and install in our system. But this is not recommend way to install the system. so use our distribution(Ubuntu, red-hat release )  kernel update. Check your Linux kernel version         In Linux system use uname -r or cat /proc/version to find the current kernel version Linux Kernel Version here 2.6.35.22  is current system kernel version Step 1 : Download the latest kernel  Goto  http://kernel.org/  website and get the latest version of the kernel source. i will get 3.3.3

In my last post ( Virtual Host in Tomcat ) we discussed about how setup the virtual host in Tomcat. Its cost effective technique because only one public IP is enough to host multiple domain. If we have big organization and each department want to host their website in locally in different machine. then how to achieve the virtual host concept?. In this post we will see the how we do this. Update :   I posted  Virtual Host + Nginx + Tomcat  Its easy to configure, compare to Apache httpd server Problem Scenario:         In big organization they have multiple department, each department want to host their website in different machine. so these websites are accessed locally with different local IP address. When we mapping to public address then we face the problem. We have two choice either purchase as many public address or Put one server front  and delegate these request.  We going to use 2nd option. we put Apache httpd web server in front of all department servers. so onl

Hi in this post we will see how to setup virtual host in Apache Tomcat server. Virtual Host is in-built feature that allows to deploy multiple website(domains) in single instance of tomcat server. The main benefit in this way is its cost effective. Scenario: I am going to deploy 3 website with following domain names in single tomcat http://www.ramki.com http://www.krishnan.com http://www.blog.ramki.com The following diagram is my outline. Outline structure of Virtual Host Concept in Tomcat Here my tomcat IP address 192.168.1.15. or any IP address allocated my ISP. but it should be public IP address. How all domain names are pointing to my Tomcat?                   When we purchase the domain name we need to update the our tomcat IP address to it. like or we can simulate same DNS Setup through hosts file in both Linux and Windows. In Linux tha file is located at /etc/hosts Now How Setup Virtual Host Concept? Before going to setup the virtual host. first tak