private boolean isEmpty(CopyConfiguration copyConfiguration) {
        if (copyConfiguration == null) {
            return true;
        }
        List<Entry> copyEntries = copyConfiguration.getEntries();
        return copyEntries == null || copyEntries.isEmpty();
    }
Whether to copy from all containers matching configured images or only from the newest ones.
src/main/java/io/fabric8/maven/docker/CopyMojo.java