What do these different execution environments in Eclipse mean?

Question

What are the differences between these different Execution environments I'm seeing in Eclipse? It seems they're all under the same JDK version. I'm particularly interested in:

• What do they represent exactly?
• When will I choose one over the other? The J2SE ones are straightforward, but what are those CDC and OSGi for?

Answer 1

This link should answer your question:

Execution environments (EEs) are symbolic representations of JREs. For example, rather than talking about a specific JRE, with a specific name at a specific location on your disk, you can talk about the J2SE-1.4 execution environment. The system can then be configured to use a specific JRE to implement that execution environment. Execution environments are relevant both to development (compile) time and runtime.