Minecraft wiki entry for The_End, associated text: In Java Edition, due to a bug[1], the outer End islands fail to generate in multiple concentic rings. The first ring starts at ±370,727 on the X and Z axes, cutting off terrain generation in a doughnut shape. It continues empty, but comes back at X/Z=(-)524,288, then disappears again at X/Z=(-)642,119 and comes back at X/Z=(-)741,455. It continues like this all the way until the world border, getting closer and closer. If the world border would be removed, going far enough would lead to world looking slightly like the stripe lands of Bedrock Edition.