Can not find the declaration of element 'persistence'

Question

Have put the persistence.xml in the classpath of the project in eclipse because before the error was that the file was not found. Now gives this error:

<

Answer 1

The problem is that you mix JPA 2.0 and JPA 2.1 notation.

Either this

for JPA 2.1 or this

for JPA 2 but not a mix thereof.

See http://www.oracle.com/webfolder/technetwork/jsc/xml/ns/persistence/index.html for details.