Liferay Portal is the world's leading open source enterprise portal solution using the latest in Java and Web 2.0 technologies.
1. Runs on all major application servers and servlet containers, databases, and operating
systems, with over 700 deployment combinations
2. JSR-286 Compliant
3. Out-of-the-box usability with over 60 portlets pre-bundled.
4. Built in Content Management System (CMS) and Collaboration Suite
5. Personalized pages for all users
6. Benchmarked as among the most secure portal platforms using LogicLibrary's
Created for the enterprise, Liferay Portal provides a virtual space where you can
centralize, share and collaborate.
Check this link to understand why Liferay is a better alternative to Sharepoint.