Java 9 specific class files in
/META-INF/versions/9/ folder
in the multi-release module
$JBOSS_HOME/modules/system/layers/base/javax/orb/api/main/openjdk-orb-8.0.8.Final-redhat-1.jar
are missing source file in jboss-eap-7.1.0.ER2.2-maven-repository.zip

Actually there are only .class (instead of expected .java) files in
jboss-eap-7.1.0.ER2.2-maven-repository.zip/jboss-eap-7.1.0.GA-maven-repository/maven-repository/org/jboss/openjdk-orb/openjdk-orb/8.0.8.Final-redhat-1/openjdk-orb-8.0.8.Final-redhat-1-sources.jar/META-INF/versions/9/