@SuppressWarnings("unchecked")
    private Object createExtension(final ClassEntity classEntity) {
        Class<?> aClass = classEntity.getClazz();
        try {
            return aClass.newInstance();
        } catch (InstantiationException | IllegalAccessException e) {
            throw new IllegalStateException("Extension instance(name: " + classEntity.getName() + ", class: "
                    + aClass + ")  could not be instantiated: " + e.getMessage(), e);

        }
    }
get all join spi.

@return list. joins
shenyu-spi/src/main/java/org/apache/shenyu/spi/ExtensionLoader.java