Hi Karthik,
1. Is WSRP is fading as an integration method and instead, people are moving towards RESTful service method ?
Each has its own usages and benefits, It depends on ones choice but yes, RESTful services are becoming popular.
2. Does Liferay require J2EE container or just a Web Container like Tomcat ?
Liferay works well on a Web Container like Tomcat. Liferay comes bundled with Tomcat, JBoss etc
3. What is the popular IDE tool for developing Liferay Portlets ?
Liferay IDE provided by Liferay itself for application development for Liferay Portal. Liferay Developer Studio is also available that comes bundled with Eclipse and Plugin SDK.
Does Liferay support an MVC structure, say Struts ?
Yes, even all the OOB portlets are developed using Struts MVC itself. you can also make use of any framework that supports MVC like spring etc
