diff --git a/src/main/java/com/Acrobot/ChestShop/ChestShop.java b/src/main/java/com/Acrobot/ChestShop/ChestShop.java
index 21fdc76..ec68890 100644
--- a/src/main/java/com/Acrobot/ChestShop/ChestShop.java
+++ b/src/main/java/com/Acrobot/ChestShop/ChestShop.java
@@ -179,9 +179,11 @@ public class ChestShop extends JavaPlugin {
 
     private void registerCommand(String name, CommandExecutor executor, Permission permission) {
         PluginCommand command = getCommand(name);
-        command.setExecutor(executor);
-        command.setPermission(permission.toString());
-        commands.add(command);
+        if (command != null) {
+            command.setExecutor(executor);
+            command.setPermission(permission.toString());
+            commands.add(command);
+        }
     }
 
     public void loadConfig() {
@@ -244,7 +246,7 @@ public class ChestShop extends JavaPlugin {
             try {
                 previousVersion.save(versionFile);
             } catch (IOException e) {
-                e.printStackTrace();
+                getLogger().log(java.util.logging.Level.SEVERE, "Unable to save new database version " + Migrations.CURRENT_DATABASE_VERSION, e);
             }
         }
 
@@ -261,7 +263,7 @@ public class ChestShop extends JavaPlugin {
             try {
                 previousVersion.save(versionFile);
             } catch (IOException e) {
-                e.printStackTrace();
+                getLogger().log(java.util.logging.Level.SEVERE, "Unable to save new database version " + newVersion, e);
             }
         }
         return true;
@@ -282,7 +284,7 @@ public class ChestShop extends JavaPlugin {
 
                 file.createNewFile();
             } catch (IOException e) {
-                e.printStackTrace();
+                getBukkitLogger().log(java.util.logging.Level.SEVERE, "Unable to load file " + file.getName(), e);
             }
         }
 
@@ -295,7 +297,7 @@ public class ChestShop extends JavaPlugin {
         try {
             handler = new FileHandler(path, true);
         } catch (IOException ex) {
-            ex.printStackTrace();
+            getBukkitLogger().log(java.util.logging.Level.SEVERE, "Unable to load handler " + path, ex);
         }
 
         return handler;
@@ -437,8 +439,8 @@ public class ChestShop extends JavaPlugin {
 
     private void startStatistics() {
         Metrics bStats = new Metrics(this, 1109);
-        try {
-            String dist = new JarFile(this.getFile()).getManifest().getMainAttributes().getValue("Distribution-Type");
+        try (JarFile jarFile = new JarFile(this.getFile())) {
+            String dist = jarFile.getManifest().getMainAttributes().getValue("Distribution-Type");
             bStats.addCustomChart(new SimplePie("distributionType", () -> dist));
         } catch (IOException ignored) {}
 
diff --git a/src/main/java/com/Acrobot/ChestShop/Metadata/ItemDatabase.java b/src/main/java/com/Acrobot/ChestShop/Metadata/ItemDatabase.java
index 287f6c8..9a22ad2 100644
--- a/src/main/java/com/Acrobot/ChestShop/Metadata/ItemDatabase.java
+++ b/src/main/java/com/Acrobot/ChestShop/Metadata/ItemDatabase.java
@@ -70,8 +70,10 @@ public class ItemDatabase {
     private int getCurrentMetadataVersion() {
         ItemStack item = new ItemStack(Material.STONE);
         ItemMeta meta = item.getItemMeta();
-        meta.setDisplayName("GetCurrentMetadataVersion");
-        item.setItemMeta(meta);
+        if (meta != null) {
+            meta.setDisplayName("GetCurrentMetadataVersion");
+            item.setItemMeta(meta);
+        }
         Map<String, Object> serialized = item.serialize();
         return (int) serialized.getOrDefault("v", -1);
     }
@@ -117,7 +119,7 @@ public class ItemDatabase {
                 return true;
             });
         } catch (Exception e) {
-            e.printStackTrace();
+            ChestShop.getBukkitLogger().log(Level.SEVERE, "Unable to update metadata version of all items from " + previousVersion + " to " + newVersion, e);
             return false;
         } finally {
             it.closeQuietly();
@@ -153,10 +155,8 @@ public class ItemDatabase {
                 itemDao.create(itemEntity);
             }
             return Base62.encode(itemEntity.getId());
-        } catch (SQLException e) {
-            e.printStackTrace();
-        } catch (IOException e) {
-            e.printStackTrace();
+        } catch (SQLException | IOException e) {
+            ChestShop.getBukkitLogger().log(Level.SEVERE, "Unable to get code of item " + item, e);
         }
 
         return null;
@@ -196,7 +196,7 @@ public class ItemDatabase {
         return null;
     }
 
-    private class YamlBukkitConstructor extends YamlConstructor {
+    private static class YamlBukkitConstructor extends YamlConstructor {
         public YamlBukkitConstructor() {
             this.yamlConstructors.put(new Tag(Tag.PREFIX + "org.bukkit.inventory.ItemStack"), yamlConstructors.get(Tag.MAP));
         }