Sometimes there is a need to apply java code changes without complete application rebuild and Tomcat restart. The main idea here is just to copy compiled java classes to the application directory under Tomcat.

There are many complaining posts online telling about almost impossible wifi adapter installation within CentOS. After a quick look at the forums dedicated to this problem I’ve got an impression that nowadays very few adapters could be installed in CentOS and people ask which exact usb wifi will work by them for sure. In this article I’ll provide a complete approach how to install a usb wifi for your server (CentOS 7 minimal, command line only).

In previous post Liferay Spring MVC Portlet (+JPA, Maven) part.1 I wrote how to develop a Liferay Spring Portlet using Maven, in this article I’ll discuss how to inject the JPA ORM in it.

Recently we’ve received a new request by our client to implement a Liferay Portlet that uses JPA as a primary ORM-system. Sure, Liferay provides Service Builders that enable ORM functionality in portlets, but I was always wondering why some companies prefer to develop their own frameworks instead of using already existing good solutions. So in this task we had to move from Liferay ORM + Liferay Transactions to well known and mature frameworks: Java JPA + Spring.

In one of my previous articles AlloyUI tables in Liferay Application Display Templates (ADT) I wrote about table creation in Liferay ADT using AlloyUI. In this article I’ll demonstrate how to do it via liferay-ui (http://liferay.com/tld/ui) and liferay-portlet (http://java.sun.com/portlet) tag libraries (tlds). The usage of tag libraries instead of AlloyUI javascript library gives a more elegant way to define tables.

Sometimes in Liferay there is a necessity to implement your own jsp taglib (tld) for some portlets. At first sight this issue might seem trivial (just to follow a standard jsp tag library development process), in Liferay context it becomes not so easy. By default all Liferay jsp tags extend Liferay TagSupport class which keeps servletContext variable. The thing here is that this servletContext is a context of ROOT application. This means that all resources required for new taglib will be searched at ROOT application directory of your application container. Yes, we can store all needed resources at ROOT app, but this is a bad practice while Liferay core (ROOT app) should be always separate from customizations. In this article there is an approach and an example to overcome this issue.

Most posts on the internet regarding "How to build a war file of Liferay portlet" topic, cover only Ant tool. I find Maven as a next-gen project build tool and in this post I'll show how to use it to build Liferay portlet war.

The application display template (ADT) framework allows portal administrators to change portlet’s GUI by means of freemarker/velocity template engine on-the-fly, without portlet restart. Template engine can use standard liferay AlloyUI taglib (http://liferay.com/tld/aui) to define visual representation. That is great for sure, but current taglib does not include all often used user components. For example, there is no support of tables. In this article I’ll show how to define a table in Freemarker template using AlloyUI library and put it to portlet.