Fix LowerCase/Session Stolen issue

src/main/java/fr/xephi/authme/DataManager.java

@@ -46,6 +46,8 @@ public class DataManager {
             return result.get();
         } catch (Exception e) {
             return (null);
+        } finally {
+            executor.shutdown();
         }
     }
 
@@ -159,4 +161,32 @@ public class DataManager {
         }
         ConsoleLogger.info("AutoPurgeDatabase : Remove " + i + " Permissions");
     }
+
+    public boolean isOnline(Player player, final String name) {
+        if (player.isOnline())
+            return true;
+        ExecutorService executor = Executors.newSingleThreadExecutor();
+        Future<Boolean> result = executor.submit(new Callable<Boolean>() {
+
+            public synchronized Boolean call() throws Exception {
+                Boolean result = null;
+                try {
+                    for (OfflinePlayer op : Bukkit.getOnlinePlayers())
+                        if (op.getName().equalsIgnoreCase(name)) {
+                            result = true;
+                            break;
+                        }
+                } catch (Exception e) {
+                }
+                return result;
+            }
+        });
+        try {
+            return result.get().booleanValue();
+        } catch (Exception e) {
+            return (false);
+        } finally {
+            executor.shutdown();
+        }
+    }
 }

src/main/java/fr/xephi/authme/listener/AuthMePlayerListener.java

@@ -446,21 +446,22 @@ public class AuthMePlayerListener implements Listener {
 
         // Check if forceSingleSession is set to true, so kick player that has
         // joined with same nick of online player
-        if (player.isOnline() && Settings.isForceSingleSessionEnabled) {
+        if (plugin.dataManager.isOnline(player, name) && Settings.isForceSingleSessionEnabled) {
             event.setKickMessage(m.send("same_nick")[0]);
             event.setResult(PlayerLoginEvent.Result.KICK_OTHER);
-            Bukkit.getScheduler().runTaskAsynchronously(plugin, new Runnable() {
+            if (LimboCache.getInstance().hasLimboPlayer(name))
+                Bukkit.getScheduler().runTaskAsynchronously(plugin, new Runnable() {
 
-                @Override
+                    @Override
-                public void run() {
+                    public void run() {
-                    LimboPlayer limbo = LimboCache.getInstance().getLimboPlayer(player.getName().toLowerCase());
+                        LimboPlayer limbo = LimboCache.getInstance().getLimboPlayer(player.getName().toLowerCase());
-                    if (PlayerCache.getInstance().isAuthenticated(player.getName().toLowerCase())) {
+                        if (player != null && limbo != null && PlayerCache.getInstance().isAuthenticated(player.getName().toLowerCase())) {
-                        Utils.getInstance().addNormal(player, limbo.getGroup());
+                            Utils.getInstance().addNormal(player, limbo.getGroup());
-                        LimboCache.getInstance().deleteLimboPlayer(player.getName().toLowerCase());
+                            LimboCache.getInstance().deleteLimboPlayer(player.getName().toLowerCase());
+                        }
                     }
-                }
 
-            });
+                });
             return;
         }