Try the example described in https://jira.jboss.org/jira/browse/JBIDE-4736?focusedCommentId=12482337#action_12482337
If you try to deploy the booking-ear application, libraries in booking/WEB-INF/lib won't be deployed.
booking/.settings/org.eclipse.wst.common.component contains the following:

<?xml version="1.0" encoding="UTF-8"?>
<project-modules id="moduleCoreId" project-version="1.5.0">
<wb-module deploy-name="booking">
<wb-resource deploy-path="/" source-path="/src/main/webapp"/>
<wb-resource deploy-path="/WEB-INF/classes" source-path="/src/main/java"/>
<wb-resource deploy-path="/WEB-INF/classes" source-path="/src/resources"/>
<property name="context-root" value="booking"/>
<property name="java-output-path"/>
</wb-module>
</project-modules>

if you call Maven>Update Project Configuration, booking/.settings/org.eclipse.wst.common.component will look as follows:

<?xml version="1.0" encoding="UTF-8"?>
<project-modules id="moduleCoreId" project-version="1.5.0">
<wb-module deploy-name="booking">
<wb-resource deploy-path="/" source-path="/src/main/webapp"/>
<wb-resource deploy-path="/WEB-INF/classes" source-path="/src/main/java"/>
<wb-resource deploy-path="/WEB-INF/classes" source-path="/src/resources"/>
<wb-resource deploy-path="/" source-path="/src/main/webapp"/>
<property name="context-root" value="booking"/>
<property name="java-output-path"/>
</wb-module>
</project-modules>

the libraries in booking/WEB-INF/lib will be deployed correctly.
The problem exists when using JBoss Tools servers as well as using JBoss WTP Generic servers.
The problem doesn't exist when using Export>Java EE>EAR File.

PS
The WEB-INF/lib directory and the required libraries are unnecessary added to the EAR's root directory, but this issue is fixed with the patch attached to https://bugs.eclipse.org/bugs/show_bug.cgi?id=247090.