Update

src/main/scala/io/izzel/taboolib/common/event/PlayerAttackEvent.java

@@ -6,8 +6,8 @@ import org.bukkit.entity.Player;
 
 public class PlayerAttackEvent extends EventCancellable<PlayerAttackEvent> {
 
-    private Player player;
-    private Entity target;
+    private final Player player;
+    private final Entity target;
 
     public PlayerAttackEvent(Player player, Entity target) {
         this.player = player;

src/main/scala/io/izzel/taboolib/common/event/PlayerJumpEvent.java

@@ -5,7 +5,7 @@ import org.bukkit.entity.Player;
 
 public class PlayerJumpEvent extends EventCancellable<PlayerJumpEvent> {
 
-    private Player player;
+    private final Player player;
 
     public PlayerJumpEvent(Player player) {
         this.player = player;

src/main/scala/io/izzel/taboolib/common/listener/ListenerCommand.java

@@ -46,7 +46,7 @@ public class ListenerCommand implements Listener {
         StartupLoader.register(ListenerCommand.class);
     }
 
-    abstract class Module {
+    abstract static class Module {
 
         abstract public String[] name();
 

src/main/scala/io/izzel/taboolib/common/listener/ListenerPlayerJump.java

@@ -14,7 +14,7 @@ import org.bukkit.event.player.PlayerMoveEvent;
 public class ListenerPlayerJump implements Listener {
 
     @TInject
-    private static Cooldown cooldown = new Cooldown("taboolib:jump", 350);
+    private static final Cooldown cooldown = new Cooldown("taboolib:jump", 350);
 
     @EventHandler(priority = EventPriority.HIGH, ignoreCancelled = true)
     public void onJump(PlayerMoveEvent e) {

src/main/scala/io/izzel/taboolib/common/loader/StartupLoader.java

@@ -12,6 +12,7 @@ import java.util.List;
  * @Author sky
  * @Since 2020-03-24 23:54
  */
+@SuppressWarnings("rawtypes")
 public class StartupLoader {
 
     static List<Class<?>> classList = Lists.newArrayList();

src/main/scala/io/izzel/taboolib/common/plugin/InternalPlugin.java

@@ -24,7 +24,7 @@ import java.util.logging.Logger;
  */
 public class InternalPlugin implements Plugin {
 
-    private static InternalPlugin plugin;
+    private static final InternalPlugin plugin;
 
     public static InternalPlugin getPlugin() {
         return plugin;

src/main/scala/io/izzel/taboolib/common/plugin/InternalPluginLoader.java

@@ -17,7 +17,7 @@ import java.util.regex.Pattern;
  */
 public class InternalPluginLoader implements PluginLoader {
 
-    private static JavaPluginLoader loader;
+    private static final JavaPluginLoader loader;
 
     public static PluginLoader getLoader() {
         return loader;

src/main/scala/io/izzel/taboolib/common/plugin/bridge/BridgeImpl.java

@@ -30,12 +30,13 @@ import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
 
+@SuppressWarnings("rawtypes")
 public class BridgeImpl extends InternalPluginBridge {
 
     private Object economy;
     private Object permission;
     private Method getRegionManager;
-    private boolean placeholder;
+    private final boolean placeholder;
     private boolean worldguard;
 
     public BridgeImpl() {