Maven repository validation identified several pom.xml files in Errai project which are invalid according to Maven pom XSD [1]:

• org/jboss/errai/errai-ioc/4.4.1.Final-redhat-00001/errai-ioc-4.4.1.Final-redhat-00001.pom
• org/jboss/errai/errai-navigation/4.4.1.Final-redhat-00001/errai-navigation-4.4.1.Final-redhat-00001.pom
• org/jboss/errai/errai-security-server/4.4.1.Final-redhat-00001/errai-security-server-4.4.1.Final-redhat-00001.pom
• org/jboss/errai/errai-security-client/4.4.1.Final-redhat-00001/errai-security-client-4.4.1.Final-redhat-00001.pom
• org/jboss/errai/errai-common/4.4.1.Final-redhat-00001/errai-common-4.4.1.Final-redhat-00001.pom

The validation error is the following:

cvc-complex-type.3.2.2: Attribute 'combine.self' is not allowed to appear in element 'configuration'.

When inspecting [1], it indeed allows the ``combine`` attribute in children of the ``configuration`` element, but not in the ``configuration`` element itself. It is also mentioned in the documentation:

You can control how child POMs inherit configuration from parent POMs by adding combine.children or combine.self attributes to the children of the configuration element:
...

I have tried to move the attribute to relevant children and the resulting pom.xml is valid. For quick validation, this tool [2] can be used: [3] shows an example of the violation, [4] shows a proposed fix.

[1] http://maven.apache.org/xsd/maven-4.0.0.xsd
[2] http://www.utilities-online.info/xsdvalidation
[3] http://www.utilities-online.info/xsdvalidation/?save=ffbf2a14-9419-4fd3-bb3c-56f82e592680-xsdvalidation
[4] http://www.utilities-online.info/xsdvalidation/?save=b28b1e1c-c868-4f7e-8134-ac4168d7656d-xsdvalidation