You must move persistence.xml file to an appropriate location.
More specifically, add META-INF/persistence.xml file to the root of a source folder.
In this case, the following is an appropriate location: src\main\java\META-INF\persistence.xml
Here are the details:
(taken from the JPA spec)
A persistence.xml file defines a persistence unit. The persistence.xml
file is located in the META-INF directory of the root of the
persistence unit.
The root of the persistence unit is the key here.
If you are a non-Java EE app
The jar file or directory whose META-INF directory contains the
persistence.xml file is termed the root of the persistence unit.
If you are in a Java EE app, the following are valid
In Java EE environments, the root of a persistence unit must be one of
the following:
- an EJB-JAR file
- the WEB-INF/classes directory of a WAR file[80]
- a jar file in the WEB-INF/lib directory of a WAR file
- a jar file in the EAR library directory
- an application client jar file