Simplify further as using ConcurrentHashMap

worldedit-bukkit/src/main/java/com/sk89q/worldedit/bukkit/BukkitPermissionAttachmentManager.java

@@ -19,26 +19,16 @@ public class BukkitPermissionAttachmentManager {
         if (p == null) {
             return null;
         }
-        PermissionAttachment attachment = attachments.get(p);
-
-        if (attachment != null) {
-            return attachment;
-        }
-
-        synchronized (this) {
         return attachments.computeIfAbsent(p, k -> k.addAttachment(plugin));
     }
-    }
 
     public void removeAttachment(@Nullable final Player p) {
-        if (p == null || attachments.get(p) == null) {
+        if (p == null) {
             return;
         }
-        synchronized (this) {
         PermissionAttachment attach = attachments.remove(p);
         if (attach != null) {
             p.removeAttachment(attach);
         }
     }
 }
-}