Program: 172834
Project: 172834
Buggy source:
@Override public CommandResult execute(CommandSource source,CommandContext context) throws CommandException {
  String factionName=context.<String>getOne("String_Node_Str").get();
  if (source instanceof Player) {
    Player player=(Player)source;
    if (FactionLogic.getFactionName(player.getUniqueId()) == null) {
      if (FactionLogic.getFactionsNames().contains(factionName)) {
        if (EagleFactions.AdminList.contains(player.getUniqueId().toString()))         FactionLogic.joinFaction(player.getUniqueId(),factionName);
        for (        Invite invite : EagleFactions.InviteList) {
          if (invite.getPlayerUUID().equals(player.getUniqueId()) && invite.getFactionName().equals(factionName)) {
            try {
              FactionLogic.joinFaction(player.getUniqueId(),factionName);
              EagleFactions.InviteList.remove(new Invite(factionName,player.getUniqueId()));
              source.sendMessage(Text.of(PluginInfo.PluginPrefix,TextColors.GREEN,"String_Node_Str",TextColors.GOLD,factionName));
              return CommandResult.success();
            }
 catch (            Exception exception) {
              exception.printStackTrace();
            }
          }
        }
        source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str"));
      }
 else {
        source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str",TextColors.GOLD,factionName));
      }
    }
 else {
      source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str"));
    }
  }
 else {
    source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str"));
  }
  return CommandResult.success();
}

Fixed version (ground truth):
@Override public CommandResult execute(CommandSource source,CommandContext context) throws CommandException {
  String factionName=context.<String>getOne("String_Node_Str").get();
  if (source instanceof Player) {
    Player player=(Player)source;
    if (FactionLogic.getFactionName(player.getUniqueId()) == null) {
      if (FactionLogic.getFactionsNames().contains(factionName)) {
        if (EagleFactions.AdminList.contains(player.getUniqueId().toString())) {
          FactionLogic.joinFaction(player.getUniqueId(),factionName);
          source.sendMessage(Text.of(PluginInfo.PluginPrefix,TextColors.GREEN,"String_Node_Str",TextColors.GOLD,factionName));
          return CommandResult.success();
        }
        for (        Invite invite : EagleFactions.InviteList) {
          if (invite.getPlayerUUID().equals(player.getUniqueId()) && invite.getFactionName().equals(factionName)) {
            try {
              FactionLogic.joinFaction(player.getUniqueId(),factionName);
              EagleFactions.InviteList.remove(new Invite(factionName,player.getUniqueId()));
              source.sendMessage(Text.of(PluginInfo.PluginPrefix,TextColors.GREEN,"String_Node_Str",TextColors.GOLD,factionName));
              return CommandResult.success();
            }
 catch (            Exception exception) {
              exception.printStackTrace();
            }
          }
        }
        source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str"));
      }
 else {
        source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str",TextColors.GOLD,factionName));
      }
    }
 else {
      source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str"));
    }
  }
 else {
    source.sendMessage(Text.of(PluginInfo.ErrorPrefix,TextColors.RED,"String_Node_Str"));
  }
  return CommandResult.success();
}