Use a reliable world generation method or a trusted server to prevent blocks from appearing again.
Use a reliable world generation method or a trusted server to prevent blocks from appearing again.
Increase memory allocation. Also, check out the site at http://www.minecraftforum.net/
Does it seem like the item appears again once you mine it? Are you on a multiplayer server? You may need to upgrade your computer or reinstall the game.
Consider upgrading to a newer processor and graphics card for better performance.
You only need xmx and xmn, it’s pointless to set a minimum limit