protected Method tryInstanceMethod(final Class clazz) {
        Method instanceMethod;
        try {
            instanceMethod = clazz.getDeclaredMethod("instance");
        } catch (Exception methodex) {
            instanceMethod = null;
        }

        if (null == instanceMethod) {
            try {
                instanceMethod = clazz.getDeclaredMethod("getInstance");
            } catch (Exception methodex) {
                instanceMethod = null;
            }
        }

        return instanceMethod;
    }
Reads a list of fully qualified class names from the value of the {@link #TOKEN_IO_REGISTRIES} configuration
key. These classes should equate to {@link IoRegistry} implementations that will be assigned to the
{@link Mapper.Builder}.  The assumption is that the {@link IoRegistry} either has a static {@code instance()}
method or has a zero-arg constructor from which it can be instantiated.
gremlin-util/src/main/java/org/apache/tinkerpop/gremlin/util/ser/AbstractMessageSerializer.java