diff --git a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Config.java b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Config.java
index 46dd281..87dea53 100644
--- a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Config.java
+++ b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Config.java
@@ -19,7 +19,6 @@
 
 import at.pcgamingfreaks.Bukkit.Configuration;
 
-import org.bukkit.Bukkit;
 import org.bukkit.ChatColor;
 import org.bukkit.GameMode;
 import org.bukkit.plugin.java.JavaPlugin;
diff --git a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Database.java b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Database.java
index 37bf1c3..1e3b9ca 100644
--- a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Database.java
+++ b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Database.java
@@ -41,7 +41,8 @@ public abstract class Database implements Listener
 
 	protected final Minepacks plugin;
 	protected final InventorySerializer itsSerializer = new InventorySerializer();
-	protected boolean useUUIDs, useUUIDSeparators;
+	protected final boolean useUUIDs;
+	protected boolean useUUIDSeparators;
 	protected long maxAge;
 	private final Map<OfflinePlayer, Backpack> backpacks = new ConcurrentHashMap<>();
 	private final UnCacheStrategie unCacheStrategie;
diff --git a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Files.java b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Files.java
index 5f0b010..37ef6ab 100644
--- a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Files.java
+++ b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/Files.java
@@ -21,7 +21,6 @@
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.FilenameFilter;
-import java.util.Date;
 
 import javax.swing.filechooser.FileFilter;
 
@@ -82,7 +81,10 @@ private void checkFiles()
 			{
 				if(len <= 16) // It's a player name
 				{
-					file.renameTo(new File(saveFolder, UUIDConverter.getUUIDFromName(file.getName().substring(0, len), true, useUUIDSeparators) + EXT));
+					if(!file.renameTo(new File(saveFolder, UUIDConverter.getUUIDFromName(file.getName().substring(0, len), true, useUUIDSeparators) + EXT)))
+					{
+						plugin.getLogger().warning("Failed to rename file (" + file.getAbsolutePath() + ").");
+					}
 				}
 				else // It's an UUID
 				{
@@ -90,14 +92,20 @@ private void checkFiles()
 					{
 						if(!useUUIDSeparators)
 						{
-							file.renameTo(new File(saveFolder, file.getName().replaceAll("-", "")));
+							if(!file.renameTo(new File(saveFolder, file.getName().replaceAll("-", ""))))
+							{
+								plugin.getLogger().warning("Failed to rename file (" + file.getAbsolutePath() + ").");
+							}
 						}
 					}
 					else
 					{
 						if(useUUIDSeparators)
 						{
-							file.renameTo(new File(saveFolder, file.getName().replaceAll("(\\w{8})(\\w{4})(\\w{4})(\\w{4})(\\w{12})" + EXT_REGEX, "$1-$2-$3-$4-$5" + EXT)));
+							if(!file.renameTo(new File(saveFolder, file.getName().replaceAll("(\\w{8})(\\w{4})(\\w{4})(\\w{4})(\\w{12})" + EXT_REGEX, "$1-$2-$3-$4-$5" + EXT))))
+							{
+								plugin.getLogger().warning("Failed to rename file (" + file.getAbsolutePath() + ").");
+							}
 						}
 					}
 				}
@@ -170,7 +178,7 @@ public Backpack loadBackpack(OfflinePlayer player)
 	
 	private static class BackpackFileFilter extends FileFilter implements FilenameFilter
 	{
-		String description, extension;
+		final String description, extension;
 
 		public BackpackFileFilter()
 		{
diff --git a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/InventorySerializer.java b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/InventorySerializer.java
index f38eb5e..e676fff 100644
--- a/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/InventorySerializer.java
+++ b/src/at/pcgamingfreaks/Minepacks/Bukkit/Database/InventorySerializer.java
@@ -27,7 +27,8 @@
 
 public class InventorySerializer
 {
-	private ItemStackSerializer serializer, baseItemStackSerializer = new BukkitItemStackSerializer();
+	private static final ItemStackSerializer BUKKIT_ITEM_STACK_SERIALIZER = new BukkitItemStackSerializer();
+	private ItemStackSerializer serializer;
 	private int usedSerializer = 1;
 	
 	public InventorySerializer()
@@ -48,7 +49,7 @@ public InventorySerializer()
 		if(serializer == null)
 		{
 			usedSerializer = 0;
-			serializer = baseItemStackSerializer;
+			serializer = BUKKIT_ITEM_STACK_SERIALIZER;
 		}
 	}
 	
@@ -68,7 +69,7 @@ public ItemStack[] deserialize(byte[] data, int usedSerializer)
 		if(data == null) return null;
 		switch(usedSerializer)
 		{
-			case 0: return baseItemStackSerializer.deserialize(data);
+			case 0: return BUKKIT_ITEM_STACK_SERIALIZER.deserialize(data);
 			default: return serializer.deserialize(data);
 		}
 	}
diff --git a/src/at/pcgamingfreaks/Minepacks/Bukkit/Listener/EventListener.java b/src/at/pcgamingfreaks/Minepacks/Bukkit/Listener/EventListener.java
index d788f41..8c21ee0 100644
--- a/src/at/pcgamingfreaks/Minepacks/Bukkit/Listener/EventListener.java
+++ b/src/at/pcgamingfreaks/Minepacks/Bukkit/Listener/EventListener.java
@@ -33,9 +33,8 @@
 
 public class EventListener implements Listener
 {
-	private Minepacks plugin;
-	
-	private Message messageOwnBackpackClose, messageOtherBackpackClose;
+	private final Minepacks plugin;
+	private final Message messageOwnBackpackClose, messageOtherBackpackClose;
 	
 	public EventListener(Minepacks mp)
 	{