Refactoring: use isEmpty() method

missilewars-plugin/src/main/java/de/butzlabben/missilewars/commands/StatsCommands.java

@@ -140,7 +140,7 @@ public class StatsCommands extends BaseCommand {
         }
         // TODO implement more features
 
-        if (recommendations.size() == 0) {
+        if (recommendations.isEmpty()) {
             player.sendMessage(Messages.getPrefix() + "§aThere are currently no recommendations, everything seems fine :)");
         } else {
             player.sendMessage(Messages.getPrefix() + "§7=====[ §eMissileWars recommendations §7]=====");

missilewars-plugin/src/main/java/de/butzlabben/missilewars/game/Game.java

@@ -120,7 +120,7 @@ public class Game {
             return;
         }
 
-        if (lobby.getPossibleArenas().size() == 0) {
+        if (lobby.getPossibleArenas().isEmpty()) {
             Logger.ERROR.log("At least one valid arena must be set at lobby \"" + lobby.getName() + "\".");
             return;
         }

missilewars-plugin/src/main/java/de/butzlabben/missilewars/game/MapVoting.java

@@ -103,7 +103,7 @@ public class MapVoting {
     private Arena getVotedArena() {
 
         // If no one voted:
-        if (arenaVotes.size() == 0) return game.getLobby().getArenas().get(0);
+        if (arenaVotes.isEmpty()) return game.getLobby().getArenas().get(0);
 
         Arena arena = arenaVotes.values().stream().collect(Collectors.groupingBy(Function.identity(), Collectors.counting()))
                 .entrySet()

missilewars-plugin/src/main/java/de/butzlabben/missilewars/game/timer/LobbyTimer.java

@@ -42,7 +42,7 @@ public class LobbyTimer extends Timer implements Runnable {
 
     @Override
     public void tick() {
-        if (getGame().getPlayers().size() == 0) return;
+        if (getGame().getPlayers().isEmpty()) return;
 
         for (MWPlayer mwPlayer : getGame().getPlayers().values()) {
             if (mwPlayer.getPlayer() == null) continue;

missilewars-plugin/src/main/java/de/butzlabben/missilewars/inventory/pages/PageGUICreator.java

@@ -62,7 +62,7 @@ public class PageGUICreator<T> {
 
     public void show(Player p) {
         List<OrcItem> items = elements.stream().map(converter::convert).collect(Collectors.toList());
-        if (items.size() == 0)
+        if (items.isEmpty())
             return;
 
         int pages = (int) (Math.ceil((items.size() / (double) elementsPerPage) < 1 ? 1 : Math.ceil((double) items.size() / (double) elementsPerPage)));