Eclipse does not recognize content of persistence.xml

Question

Im getting the following error in eclipse:

The persistence.xml file does not have recognized content.

My persistence.xml file works great in my application but eclipse keeps giving me this error. I got this after moving the file and updating my project configuration with m2eclipse. I did not change the file itself. Anyone knows how to solve this?

persistence.xml:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
    <persistence-unit name="localDB" transaction-type="RESOURCE_LOCAL">

        <provider>org.apache.openjpa.persistence.PersistenceProviderImpl</provider>
        <class>package.Users</class>
        <properties>
            <!-- enable warnings for debugging -->
            <property name="openjpa.Log" value="DefaultLevel=TRACE, Runtime=INFO, Tool=INFO, SQL=TRACE"/>
            <!-- connection properties -->
            <property name="openjpa.ConnectionURL" value="jdbc:mysql://localhost/test"/>
            <property name="openjpa.ConnectionDriverName" value="com.mysql.jdbc.Driver"/>
            <property name="openjpa.ConnectionUserName" value="root"/>
            <property name="openjpa.ConnectionPassword" value=""/>

        </properties>
    </persistence-unit>
</persistence>

Update

Looks like a bug in m2eclipse in combination with jpa.

https://bugs.eclipse.org/bugs/show_bug.cgi?id=251323

Temporarily solved by setting the option to show it as a warning instead of an error

Answer 1

I fixed the problem the following way (I'm using RAD v8.5.1):

1. Windows --> Preferences --> Validation
2. Scroll down to "JPA Validator" and click on the Ellipses under Settings.
3. Click on the "Add Include Group..." button.
4. Click on the new Include Group that appeared to highlight it.
5. Click on the "Add Rule..." button.
6. A dialog menu pops up. Click the "Folder or file name" radio button and click on "Next".
7. Click on "Browse Folder..." and navigate to your src directory (in my case, it was "src/main/resources") within your project (my project was a .war in a multi module app) in your workspace.
8. Click on "Finish".
9. Click on "OK". This will prompt a full build.
10. The error will go away.

Answer 2

Had same problem with error

The persistence.xml file does not have recognized content

Fixed by editing file in eclipse, any edit will do. And after saving error got away.

Answer 3

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
version="2.0">

Worked for me!