refactor: replace size() == 0 with isEmpty()

src/main/java/emu/grasscutter/server/http/dispatch/RegionHandler.java

@@ -53,12 +53,12 @@ public final class RegionHandler implements Router {
         var usedNames = new ArrayList<String>(); // List to check for potential naming conflicts.
 
         var configuredRegions = new ArrayList<>(DISPATCH_INFO.regions);
-        if (Grasscutter.getRunMode() != ServerRunMode.HYBRID && configuredRegions.size() == 0) {
+        if (Grasscutter.getRunMode() != ServerRunMode.HYBRID && configuredRegions.isEmpty()) {
             Grasscutter.getLogger()
                     .error(
                             "[Dispatch] There are no game servers available. Exiting due to unplayable state.");
             System.exit(1);
-        } else if (configuredRegions.size() == 0)
+        } else if (configuredRegions.isEmpty())
             configuredRegions.add(
                     new Region(
                             "os_usa",

src/main/java/emu/grasscutter/server/http/documentation/HandbookHandler.java

@@ -26,7 +26,7 @@ public final class HandbookHandler implements Router {
      */
     public HandbookHandler() {
         this.handbook = new String(FileUtils.readResource("/html/handbook.html"));
-        this.serve = HANDBOOK.enable && this.handbook.length() > 0;
+        this.serve = HANDBOOK.enable && !this.handbook.isEmpty();
 
         var server = HANDBOOK.server;
         if (this.serve && server.enforced) {

src/main/java/emu/grasscutter/server/packet/recv/HandlerClientAbilitiesInitFinishCombineNotify.java

@@ -26,7 +26,7 @@ public class HandlerClientAbilitiesInitFinishCombineNotify extends PacketHandler
                 player.getClientAbilityInitFinishHandler().addEntry(ability.getForwardType(), ability);
             }
 
-            if (entry.getInvokesList().size() > 0) {
+            if (!entry.getInvokesList().isEmpty()) {
                 session.getPlayer().getClientAbilityInitFinishHandler().update(session.getPlayer());
             }
         }

src/main/java/emu/grasscutter/server/packet/recv/HandlerClientAbilityInitFinishNotify.java

@@ -23,7 +23,7 @@ public class HandlerClientAbilityInitFinishNotify extends PacketHandler {
             player.getClientAbilityInitFinishHandler().addEntry(entry.getForwardType(), entry);
         }
 
-        if (notif.getInvokesList().size() > 0) {
+        if (!notif.getInvokesList().isEmpty()) {
             session.getPlayer().getClientAbilityInitFinishHandler().update(session.getPlayer());
         }
     }

src/main/java/emu/grasscutter/server/packet/recv/HandlerQueryPathReq.java

@@ -13,7 +13,7 @@ public class HandlerQueryPathReq extends PacketHandler {
         var req = QueryPathReq.parseFrom(payload);
 
         /** It is not the actual work */
-        if (req.getDestinationPosList().size() > 0) {
+        if (!req.getDestinationPosList().isEmpty()) {
             session.send(new PacketQueryPathRsp(req));
         }
     }

src/main/java/emu/grasscutter/server/packet/recv/HandlerSetPlayerNameReq.java

@@ -13,7 +13,7 @@ public class HandlerSetPlayerNameReq extends PacketHandler {
         // Auto template
         SetPlayerNameReq req = SetPlayerNameReq.parseFrom(payload);
 
-        if (req.getNickName() != null && req.getNickName().length() > 0) {
+        if (req.getNickName() != null && !req.getNickName().isEmpty()) {
             session.getPlayer().setNickname(req.getNickName());
             session.send(new PacketSetPlayerNameRsp(session.getPlayer()));
         }

src/main/java/emu/grasscutter/server/packet/recv/HandlerSetPlayerSignatureReq.java

@@ -13,7 +13,7 @@ public class HandlerSetPlayerSignatureReq extends PacketHandler {
         // Auto template
         SetPlayerSignatureReq req = SetPlayerSignatureReq.parseFrom(payload);
 
-        if (req.getSignature() != null && req.getSignature().length() > 0) {
+        if (req.getSignature() != null && !req.getSignature().isEmpty()) {
             session.getPlayer().setSignature(req.getSignature());
             session.send(new PacketSetPlayerSignatureRsp(session.getPlayer()));
         }

src/main/java/emu/grasscutter/server/packet/send/PacketClientAbilityInitFinishNotify.java

@@ -12,7 +12,7 @@ public class PacketClientAbilityInitFinishNotify extends BasePacket {
 
         int entityId = 0;
 
-        if (entries.size() > 0) {
+        if (!entries.isEmpty()) {
             AbilityInvokeEntry entry = entries.get(0);
             entityId = entry.getEntityId();
         }

src/main/java/emu/grasscutter/server/packet/send/PacketGetAllMailResultNotify.java

@@ -23,7 +23,7 @@ public final class PacketGetAllMailResultNotify extends BasePacket {
                         .setPacketNum(1);
 
         var inbox = player.getAllMail();
-        if (!gifts && inbox.size() > 0) {
+        if (!gifts && !inbox.isEmpty()) {
             packet.addAllMailList(
                     inbox.stream()
                             .filter(mail -> mail.stateValue == 1)

src/main/java/emu/grasscutter/server/packet/send/PacketGetOnlinePlayerListRsp.java

@@ -15,7 +15,7 @@ public class PacketGetOnlinePlayerListRsp extends BasePacket {
 
         GetOnlinePlayerListRsp.Builder proto = GetOnlinePlayerListRsp.newBuilder();
 
-        if (players.size() != 0) {
+        if (!players.isEmpty()) {
             for (Player player : players) {
                 if (player.getUid() == session.getUid()) continue;
 

src/main/java/emu/grasscutter/server/packet/send/PacketGetScenePointRsp.java

@@ -12,7 +12,7 @@ public class PacketGetScenePointRsp extends BasePacket {
 
         GetScenePointRsp.Builder p = GetScenePointRsp.newBuilder().setSceneId(sceneId);
 
-        if (GameData.getScenePointIdList().size() == 0) {
+        if (GameData.getScenePointIdList().isEmpty()) {
             for (int i = 1; i < 1000; i++) {
                 p.addUnlockedPointList(i);
                 p.addUnhidePointList(i);

src/main/java/emu/grasscutter/server/scheduler/ServerTaskScheduler.java

@@ -23,7 +23,7 @@ public final class ServerTaskScheduler {
      */
     public void runTasks() {
         // Skip if there are no tasks.
-        if (this.tasks.size() == 0) return;
+        if (this.tasks.isEmpty()) return;
 
         // Run all tasks.
         for (ServerTask task : this.tasks.values()) {