Yannick Majoros
Knowing what’s part of the spec isn’t really that difficult. Look at your imports and you’re basically done 
Migrating in a few steps? Well, you can run into issues, but it’s your fault most of the time. If you code to the standard vs your specific implementation, that promise is actually fulfilled. I do have experience with switching containers, as well as creating server-agnostic libs. That’s really a point where Java EE shines.