J2EE is Java, optimized for enterprise computing. Officially J2EE stands for Java 2 Platform, Enterprise Edition. Unlike the traditional Java, which is often used to build client enhancements, J2EE is designed to build server applications. Officially, the J2EE platform is "a set of coordinated specifications and practices that together enable solutions for developing, deploying, and managing" such server applications.
The Microsoft .NET Framework is a software framework that can be installed on computers running Microsoft Windows operating systems. It includes a large library of coded solutions to common programming problems and a virtual machine that manages the execution of programs written specifically for the framework.