my country’s patent system is an application system, which means that for the same invention and creation, the patent right belongs to whoever applies for it first, regardless of who invented it first.
However, according to Article 69 of the Patent Law, if you can prove that before applying for the patent, you have been manufacturing the same product or using the same method, or have made preparations for implementation, then you have prior use. The right of defense means that you can continue to manufacture the product and use the method within the original scope without constituting an infringement.
At the same time, you can also file a request for invalidation of the patent, and declare it invalid based on the number of the patent and the existing technology.