Generate a offline uuid based on the minecraft player name

OfflineUUID.java

import com.google.common.base.Charsets;
import java.util.UUID;

public class OfflineUUID {

    public static void main(String[] test) throws Exception {
        UUID.nameUUIDFromBytes(("OfflinePlayer:" + "playerName").getBytes(Charsets.UTF_8));
    }