ShrinkwrapWebResources.java

//Instead of
archive.merge(ShrinkWrap.create(GenericArchive.class).as(ExplodedImporter.class)
                                .importDirectory(WEBAPP_SRC).as(GenericArchive.class),
                        "/", Filters.include(".*\\.js$"))
archive.merge(ShrinkWrap.create(GenericArchive.class).as(ExplodedImporter.class)
                                .importDirectory(WEBAPP_SRC).as(GenericArchive.class),
                        "/", Filters.include(".*\\.css$"))
archive.merge(ShrinkWrap.create(GenericArchive.class).as(ExplodedImporter.class)
                                .importDirectory(WEBAPP_SRC).as(GenericArchive.class),
                        "/", Filters.include(".*\\.xhtml"))

//You can use
private static final Path WEBAPP_SRC_PATH = Paths.get("src","main","webapp");
private static final PathMatcher matcher = FileSystems.getDefault().getPathMatcher("glob:**.{xhtml,css,js}");

Files.find(WEBAPP_SRC_PATH, Integer.MAX_VALUE, (path, attr) -> matcher.matches(path))
                .forEach((p) -> archive.addAsWebResource(p.toFile(), WEBAPP_SRC_PATH.relativize(p).toString()));

couldn't you as well technically make it:

archive.merge(ShrinkWrap.create(GenericArchive.class).as(ExplodedImporter.class)
                                .importDirectory(WEBAPP_SRC).as(GenericArchive.class),
                        "/", Filters.include(".*\\.(js|css|xhtml)$"))

:)