Eclipse reports error on my JPA project

Question

Each time I make a JPA project Eclipse reports that there are errors in my project but I do not understand why it does so. I added image and errors below:

Answer 1

Old thread, however I just had the same problem and solved with an even quicker approach.

1. Project Properties --> JPA
2. Change connection to . Hit apply.
3. Change connection to previous value. Hit apply.

Hope this helps someone.