Declare nullable variants using jetbrains annotations

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/PremiumPlaceholder.java

@@ -28,6 +28,7 @@ package com.github.games647.fastlogin.bukkit;
 import me.clip.placeholderapi.expansion.PlaceholderExpansion;
 
 import org.bukkit.OfflinePlayer;
+import org.jetbrains.annotations.NotNull;
 
 public class PremiumPlaceholder extends PlaceholderExpansion {
 
@@ -40,7 +41,7 @@ public class PremiumPlaceholder extends PlaceholderExpansion {
     }
 
     @Override
-    public String onRequest(OfflinePlayer player, String identifier) {
+    public String onRequest(OfflinePlayer player, @NotNull String identifier) {
         // player is null if offline
         if (player != null && PLACEHOLDER_VARIABLE.equals(identifier)) {
             return plugin.getStatus(player.getUniqueId()).getReadableName();
@@ -50,7 +51,7 @@ public class PremiumPlaceholder extends PlaceholderExpansion {
     }
 
     @Override
-    public String getIdentifier() {
+    public @NotNull String getIdentifier() {
         return plugin.getName();
     }
 
@@ -60,12 +61,12 @@ public class PremiumPlaceholder extends PlaceholderExpansion {
     }
 
     @Override
-    public String getAuthor() {
+    public @NotNull String getAuthor() {
         return String.join(", ", plugin.getDescription().getAuthors());
     }
 
     @Override
-    public String getVersion() {
+    public @NotNull String getVersion() {
         return plugin.getDescription().getVersion();
     }
 }

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/CrackedCommand.java

@@ -31,6 +31,7 @@ import com.github.games647.fastlogin.core.StoredProfile;
 
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
+import org.jetbrains.annotations.NotNull;
 
 import static com.github.games647.fastlogin.core.shared.event.FastLoginPremiumToggleEvent.PremiumToggleReason;
 
@@ -41,7 +42,7 @@ public class CrackedCommand extends ToggleCommand {
     }
 
     @Override
-    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
         if (args.length == 0) {
             onCrackedSelf(sender, command, args);
         } else {

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/PremiumCommand.java

@@ -28,17 +28,18 @@ package com.github.games647.fastlogin.bukkit.command;
 import com.github.games647.fastlogin.bukkit.FastLoginBukkit;
 import com.github.games647.fastlogin.bukkit.event.BukkitFastLoginPremiumToggleEvent;
 import com.github.games647.fastlogin.core.StoredProfile;
+import com.github.games647.fastlogin.core.shared.event.FastLoginPremiumToggleEvent.PremiumToggleReason;
 
 import java.util.UUID;
 
-import com.github.games647.fastlogin.core.shared.event.FastLoginPremiumToggleEvent.PremiumToggleReason;
 import org.bukkit.command.Command;
 import org.bukkit.command.CommandSender;
 import org.bukkit.entity.Player;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Let users activate fast login by command. This only be accessible if
- * the user has access to it's account. So we can make sure that not another
+ * the user has access to its account. So we can make sure that not another
  * person with a paid account and the same username can steal their account.
  */
 public class PremiumCommand extends ToggleCommand {
@@ -48,7 +49,7 @@ public class PremiumCommand extends ToggleCommand {
     }
 
     @Override
-    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
+    public boolean onCommand(@NotNull CommandSender sender, @NotNull Command command, @NotNull String label, String[] args) {
         if (args.length == 0) {
             onPremiumSelf(sender, command, args);
         } else {

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/command/ToggleCommand.java

@@ -47,12 +47,12 @@ public abstract class ToggleCommand implements CommandExecutor {
     }
 
     protected boolean hasOtherPermission(CommandSender sender, Command cmd) {
-        if (!sender.hasPermission(cmd.getPermission() + ".other")) {
+        if (sender.hasPermission(cmd.getPermission() + ".other")) {
-            plugin.getCore().sendLocaleMessage("no-permission", sender);
+            return true;
-            return false;
         }
 
-        return true;
+        plugin.getCore().sendLocaleMessage("no-permission", sender);
+        return false;
     }
 
     protected boolean forwardBungeeCommand(CommandSender sender, String target, boolean activate) {

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/event/BukkitFastLoginAutoLoginEvent.java

@@ -31,6 +31,7 @@ import com.github.games647.fastlogin.core.shared.event.FastLoginAutoLoginEvent;
 import org.bukkit.event.Cancellable;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.NotNull;
 
 public class BukkitFastLoginAutoLoginEvent extends Event implements FastLoginAutoLoginEvent, Cancellable {
 
@@ -67,7 +68,7 @@ public class BukkitFastLoginAutoLoginEvent extends Event implements FastLoginAut
     }
 
     @Override
-    public HandlerList getHandlers() {
+    public @NotNull HandlerList getHandlers() {
         return handlers;
     }
 

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/event/BukkitFastLoginPreLoginEvent.java

@@ -30,6 +30,7 @@ import com.github.games647.fastlogin.core.shared.LoginSource;
 import com.github.games647.fastlogin.core.shared.event.FastLoginPreLoginEvent;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.NotNull;
 
 public class BukkitFastLoginPreLoginEvent extends Event implements FastLoginPreLoginEvent {
 
@@ -62,7 +63,7 @@ public class BukkitFastLoginPreLoginEvent extends Event implements FastLoginPreL
     }
 
     @Override
-    public HandlerList getHandlers() {
+    public @NotNull HandlerList getHandlers() {
         return handlers;
     }
 

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/event/BukkitFastLoginPremiumToggleEvent.java

@@ -29,6 +29,7 @@ import com.github.games647.fastlogin.core.StoredProfile;
 import com.github.games647.fastlogin.core.shared.event.FastLoginPremiumToggleEvent;
 import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
+import org.jetbrains.annotations.NotNull;
 
 public class BukkitFastLoginPremiumToggleEvent extends Event implements FastLoginPremiumToggleEvent {
 
@@ -53,7 +54,7 @@ public class BukkitFastLoginPremiumToggleEvent extends Event implements FastLogi
     }
 
     @Override
-    public HandlerList getHandlers() {
+    public @NotNull HandlerList getHandlers() {
         return handlers;
     }
 

bukkit/src/main/java/com/github/games647/fastlogin/bukkit/listener/BungeeListener.java

@@ -41,6 +41,7 @@ import java.util.UUID;
 import org.bukkit.Bukkit;
 import org.bukkit.entity.Player;
 import org.bukkit.plugin.messaging.PluginMessageListener;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Responsible for receiving messages from a BungeeCord instance.
@@ -57,7 +58,7 @@ public class BungeeListener implements PluginMessageListener {
     }
 
     @Override
-    public void onPluginMessageReceived(String channel, Player player, byte[] message) {
+    public void onPluginMessageReceived(@NotNull String channel, Player player, byte[] message) {
         ByteArrayDataInput dataInput = ByteStreams.newDataInput(message);
 
         LoginActionMessage loginMessage = new LoginActionMessage();
@@ -67,7 +68,7 @@ public class BungeeListener implements PluginMessageListener {
 
         Player targetPlayer = player;
         if (!loginMessage.getPlayerName().equals(player.getName())) {
-            targetPlayer = Bukkit.getPlayerExact(loginMessage.getPlayerName());;
+            targetPlayer = Bukkit.getPlayerExact(loginMessage.getPlayerName());
         }
 
         if (targetPlayer == null) {

bungee/src/main/java/com/github/games647/fastlogin/bungee/event/BungeeFastLoginPremiumToggleEvent.java

@@ -27,6 +27,7 @@ package com.github.games647.fastlogin.bungee.event;
 
 import com.github.games647.fastlogin.core.StoredProfile;
 import com.github.games647.fastlogin.core.shared.event.FastLoginPremiumToggleEvent;
+
 import net.md_5.bungee.api.plugin.Event;
 
 public class BungeeFastLoginPremiumToggleEvent extends Event implements FastLoginPremiumToggleEvent {
@@ -45,7 +46,7 @@ public class BungeeFastLoginPremiumToggleEvent extends Event implements FastLogi
     }
 
     @Override
-    public FastLoginPremiumToggleEvent.PremiumToggleReason getReason() {
+    public PremiumToggleReason getReason() {
         return reason;
     }
 }