The Samsung Galaxy J2 (SM-J200G) launched with Android 5.1.1 Lollipop. Samsung officially discontinued updates for this device after Android 6.0.1 Marshmallow. Therefore, there is no official Stock Android Oreo firmware available from Samsung for this model.
Unofficial builds like LineageOS 15.1 (based on Android 8.1 Oreo) have been developed for the J2 series by third-party creators. Higher versions like LineageOS 17.1 (Android 10) have also been ported, though they are often experimental. How to Install (Unofficial Method) android oreo for galaxy j2 sm-j200g
If you find a website claiming to offer an “Official Oreo Update” for the J2, it is either a scam, malware, or a custom ROM mislabeled. Samsung abandoned this device in 2017. To get Oreo, you must void your warranty (which is likely expired anyway) and flash a custom recovery. The Samsung Galaxy J2 (SM-J200G) launched with Android 5
Find a stable Android Oreo ROM zip and the corresponding GApps (Google Apps) for ARM architecture. Unofficial builds like LineageOS 15
