Ramki Technical Blog

 

In this post I am going to demonstrate that remotely monitor the Temperature using Raspberry Pi and MQTT protocol. This work is done  using Java code.

In this post I am going to demonstrate that how remotely control LED and how it can be connected to Raspberry Pi using MQTT protocol and control GPIO pins using pi4j library. This work is done  using Java code. Recently I bought Raspberry Pi 2, so I just wanted to do some learning stuff, basically how to blink (on/off)  LED remotely. I have performed extensive survey about Raspberry Pi on internet I found lots of stuff about connect LED with Raspberry Pi via GPIO pins. This created a lots of interest. So I m searched Java library to control gpio pins and I got pi4j library .   Actually pi4j library easy to learn and provide bunch of examples. Details of its are mentioned below:

In this post i will show Tomcat Clustering in Docker Container. In  my previous post i discussed how to achieve tomcat clustering with Nginx Front end . Its almost same scenario, but this time we will achieve via docker container. Docker Docker  is an  open-source  project that automates the deployment of  applications  inside  software containers , by providing an additional layer of abstraction and automation of  operating-system-level virtualization  on  Linux . [4]  Docker uses resource isolation features of the Linux kernel  such as  cgroups  and kernel  namespaces  to allow independent "containers" to run within a single Linux instance, avoiding the overhead of starting and maintaining  virtual machine   --Wikipedia

In this post i will show the HTML5 Support given by JSF 2.2, Which is part of Java EE 7 Spec. Also how to integrate the Bean Validation 1.1 feature with help of CDI (Contexts and Dependency Injection) 1.1 spec. Before going the HTML5 support, my earlier posts on JSF, i used @ManagedBean annotation, because its part of Managed Bean Specification (Java EE 6). Another Reason i used Tomcat as a primary container, if i used Managed Bean Spec then its part of Mojjara implementation, so no need to add more CDI specific (Jboss Weld lib) lib to class-path. But from Java EE 7 on-wards, JCP community expand the CDI capabilities and make CDI as important spec in Java EE 7 and Managed Bean spec is deprecated in favor of CDI . so they recommend to use CDI wherever its possible. so our future all post to target the CDI. next post i will show how add the CDI capability to tomcat container.

To bring the File Upload feature in Java based web application is one of the difficult and complex job, we need to dependent on 3rd party libraries like Apache Commons FileUpload  Libraries. These libraries codes are complex and most of them boilerplate code. If we are using Java Server Faces (JSF), we have the page with some fields and file upload menu the its add more complexity, fields are binded to backing bean but these file uploads components are need to tie up with some 3rd party file upload libraries. In Primefaces provide easy way to do the file upload in JSF web application, even though primefaces internally used the same Apache Commons FileUpload Libraries, but provide simple JSF tags. We need configure  some listeners.