private void initExtendHandler() {
        initExtendClass();
        Constructor<?> constructor =
                null;
        try {
            constructor = Class.forName(extendClass)
                    .getDeclaredConstructor(InstanceProfile.class);
        } catch (NoSuchMethodException e) {
            LOGGER.error("init {} NoSuchMethodException error", instanceId, e);
        } catch (ClassNotFoundException e) {
            LOGGER.error("init {} ClassNotFoundException error", instanceId, e);
        }
        constructor.setAccessible(true);
        try {
            extendedHandler = (ExtendedHandler) constructor.newInstance(profile);
        } catch (InstantiationException e) {
            LOGGER.error("init {} InstantiationException error", instanceId, e);
        } catch (IllegalAccessException e) {
            LOGGER.error("init {} IllegalAccessException error", instanceId, e);
        } catch (InvocationTargetException e) {
            LOGGER.error("init {} InvocationTargetException error", instanceId, e);
        }
    }
Returns the name of the thread, used to identify different data sources

@return source data list
inlong-agent/agent-plugins/src/main/java/org/apache/inlong/agent/plugin/sources/file/AbstractSource.java