src/main/java/org/codehaus/plexus/archiver/war/WarArchiver.java
public void addLibs( File directoryName, String[] includes, String[] excludes )
        throws ArchiverException
    {
        addDirectory( directoryName, "WEB-INF/lib/", includes, excludes );
    }
public void addLibs( File directoryName, String[] includes, String[] excludes )
        throws ArchiverException
    {
        addDirectory( directoryName, "WEB-INF/lib/", includes, excludes );
    }
add files under WEB-INF/lib/