Program: 42043
Project: 42043
Buggy source:
@SuppressWarnings("String_Node_Str") @EventHandler(priority=EventPriority.HIGH,ignoreCancelled=true) public void onPlayerInteract(PlayerInteractEvent event){
  BukkitBlock block=new BukkitBlock(event.getClickedBlock());
  if (manager.isPlotWorld(block.getWorld())) {
    Player player=event.getPlayer();
    PlotId plotId=manager.getPlotId(block.getLocation());
    PlotToClear ptc=api.getPlotLocked(block.getWorld(),plotId);
    if (ptc != null) {
switch (ptc.getReason()) {
case Clear:
        player.sendMessage(api.getUtil().C("String_Node_Str"));
      break;
case Reset:
    player.sendMessage(api.getUtil().C("String_Node_Str"));
  break;
case Expired:
player.sendMessage(api.getUtil().C("String_Node_Str"));
break;
}
event.setCancelled(true);
}
 else {
boolean canBuild=!player.hasPermission(PermissionNames.ADMIN_BUILDANYWHERE);
PlotMapInfo pmi=manager.getMap(block.getWorld());
Plot plot=manager.getPlotById(plotId,pmi);
if (event.isBlockInHand() && event.getAction() == Action.RIGHT_CLICK_BLOCK) {
if (plot == null || !plot.isAllowed(player.getName(),player.getUniqueId())) {
if (canBuild) {
player.sendMessage(api.getUtil().C("String_Node_Str"));
event.setCancelled(true);
}
}
 else {
plot.resetExpire(pmi.getDaysToExpiration());
}
}
 else {
boolean blocked=false;
if (pmi.isProtectedBlock(block.getTypeId()) && !player.hasPermission("String_Node_Str" + block.getTypeId())) {
blocked=true;
}
ItemStack item=event.getItem();
if (event.getAction() == Action.RIGHT_CLICK_BLOCK) {
if (item != null) {
int itemId=item.getType().getId();
byte itemData=item.getData().getData();
if ((pmi.isPreventedItem(String.valueOf(itemId)) || pmi.isPreventedItem(itemId + "String_Node_Str" + itemData)) && !player.hasPermission("String_Node_Str" + itemId)) {
  blocked=true;
}
}
}
if (blocked) {
if (plot == null || !plot.isAllowed(player.getName(),player.getUniqueId())) {
if (canBuild) {
  if (event.getAction() == Action.RIGHT_CLICK_BLOCK) {
    player.sendMessage(api.getUtil().C("String_Node_Str"));
  }
  event.setCancelled(true);
}
}
}
}
}
}
}

Fixed version (ground truth):
@SuppressWarnings("String_Node_Str") @EventHandler(priority=EventPriority.HIGH,ignoreCancelled=true) public void onPlayerInteract(PlayerInteractEvent event){
  BukkitBlock block=new BukkitBlock(event.getClickedBlock());
  if (manager.isPlotWorld(block.getWorld())) {
    Player player=event.getPlayer();
    PlotId plotId=manager.getPlotId(block.getLocation());
    PlotToClear ptc=api.getPlotLocked(block.getWorld(),plotId);
    if (ptc != null) {
switch (ptc.getReason()) {
case Clear:
        player.sendMessage(api.getUtil().C("String_Node_Str"));
      break;
case Reset:
    player.sendMessage(api.getUtil().C("String_Node_Str"));
  break;
case Expired:
player.sendMessage(api.getUtil().C("String_Node_Str"));
break;
}
event.setCancelled(true);
}
 else {
boolean canBuild=!player.hasPermission(PermissionNames.ADMIN_BUILDANYWHERE);
PlotMapInfo pmi=manager.getMap(block.getWorld());
Plot plot=manager.getPlotById(plotId,pmi);
if (event.isBlockInHand() && event.getAction() == Action.RIGHT_CLICK_BLOCK) {
if (plot == null || !plot.isAllowed(player.getName(),player.getUniqueId())) {
if (canBuild) {
player.sendMessage(api.getUtil().C("String_Node_Str"));
event.setCancelled(true);
}
}
 else {
plot.resetExpire(pmi.getDaysToExpiration());
}
}
 else {
boolean blocked=false;
if (pmi.isProtectedBlock(block.getTypeId()) && !player.hasPermission("String_Node_Str" + block.getTypeId())) {
blocked=true;
}
ItemStack item=event.getItem();
if (event.getAction() == Action.RIGHT_CLICK_BLOCK && item != null) {
int itemId=item.getType().getId();
byte itemData=item.getData().getData();
if ((pmi.isPreventedItem(String.valueOf(itemId)) || pmi.isPreventedItem(itemId + "String_Node_Str" + itemData)) && !player.hasPermission("String_Node_Str" + itemId)) {
blocked=true;
}
}
if (blocked) {
if (plot == null || !plot.isAllowed(player.getName(),player.getUniqueId())) {
if (canBuild) {
  if (event.getAction() == Action.RIGHT_CLICK_BLOCK) {
    player.sendMessage(api.getUtil().C("String_Node_Str"));
  }
  event.setCancelled(true);
}
}
}
}
}
}
}