private LinkedHashSet<String> readExtensionTransformletClassNames(ClassLoader classLoader) throws IOException {
        final Enumeration<URL> extensionFiles = classLoader.getResources(TTL_AGENT_EXTENSION_TRANSFORMLET_FILE);

        final Pair<LinkedHashSet<String>, Set<String>> pair = readLinesFromExtensionFiles(extensionFiles, redExtensionTransformletFileHistory);
        final LinkedHashSet<String> extensionTransformletClassNames = pair.first;
        final Set<String> stringUrls = pair.second;
        if (!stringUrls.isEmpty())
            logger.info("[TtlExtensionTransformletCollector] found TTL Extension Transformlet configuration files from classloader "
                    + classLoader + " : " + stringUrls);

        return extensionTransformletClassNames;
    }
@author Jerry Lee (oldratlee at gmail dot com)
ttl-agent/src/main/java/com/alibaba/ttl3/agent/TtlExtensionTransformletManager.java