Use modifiable and nullable collections where possible

API/src/main/java/me/filoghost/chestcommands/api/ConfigurableIcon.java

@@ -69,8 +69,6 @@ public interface ConfigurableIcon extends Icon {
 
 	void removeEnchantment(Enchantment ench);
 
-	void clearEnchantments();
-
 	Color getLeatherColor();
 
 	void setLeatherColor(Color leatherColor);

Plugin/src/main/java/me/filoghost/chestcommands/api/impl/ConfigurableIconImpl.java

@@ -41,6 +41,7 @@ import me.filoghost.chestcommands.ChestCommands;
 import me.filoghost.chestcommands.api.ClickHandler;
 import me.filoghost.chestcommands.api.ClickResult;
 import me.filoghost.chestcommands.api.ConfigurableIcon;
+import me.filoghost.chestcommands.util.Utils;
 import me.filoghost.chestcommands.variable.VariableManager;
 
 public class ConfigurableIconImpl implements ConfigurableIcon {
@@ -67,7 +68,6 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 	private ItemStack cachedItem; // When there are no variables, we don't recreate the item
 
 	public ConfigurableIconImpl() {
-		enchantments = new HashMap<>();
 		closeOnClick = true;
 		amount = 1;        
 	}
@@ -142,7 +142,7 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 
 	@Override
 	public void setLore(List<String> lore) {
-		this.lore = lore;
+		this.lore = Utils.nullableCopy(lore);
 		this.loreLinesWithVariables = null;
 
 		if (lore != null) {
@@ -159,7 +159,7 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 
 	@Override
 	public boolean hasLore() {
-		return lore != null && lore.size() > 0;
+		return !Utils.isNullOrEmpty(lore);
 	}
 
 	@Override
@@ -169,16 +169,12 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 
 	@Override
 	public void setEnchantments(Map<Enchantment, Integer> enchantments) {
-		if (enchantments == null) {
+		this.enchantments = Utils.nullableCopy(enchantments);
-			this.enchantments.clear();
-			return;
-		}
-		this.enchantments = enchantments;
 	}
 
 	@Override
 	public Map<Enchantment, Integer> getEnchantments() {
-		return new HashMap<>(enchantments);
+		return enchantments;
 	}
 
 	@Override
@@ -188,17 +184,18 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 
 	@Override
 	public void addEnchantment(Enchantment ench, Integer level) {
+		if (enchantments == null) {
+			enchantments = new HashMap<>();
+		}
 		enchantments.put(ench, level);
 	}
 
 	@Override
 	public void removeEnchantment(Enchantment ench) {
-		enchantments.remove(ench);
+		if (enchantments == null) {
+			return;
 		}
-
+		enchantments.remove(ench);
-	@Override
-	public void clearEnchantments() {
-		enchantments.clear();
 	}
 
 	@Override
@@ -239,7 +236,7 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 
 	@Override
 	public void setBannerPatterns(List<Pattern> bannerPatterns) {
-		this.bannerPatterns = bannerPatterns;
+		this.bannerPatterns = Utils.nullableCopy(bannerPatterns);
 	}
 
 	@Override
@@ -367,7 +364,7 @@ public class ConfigurableIconImpl implements ConfigurableIcon {
 
 		itemStack.setItemMeta(itemMeta);
 
-		if (enchantments.size() > 0) {
+		if (enchantments != null) {
 			for (Entry<Enchantment, Integer> entry : enchantments.entrySet()) {
 				itemStack.addUnsafeEnchantment(entry.getKey(), entry.getValue());
 			}

Plugin/src/main/java/me/filoghost/chestcommands/menu/AdvancedIconMenu.java

@@ -26,6 +26,7 @@ import me.filoghost.chestcommands.ChestCommands;
 import me.filoghost.chestcommands.Permissions;
 import me.filoghost.chestcommands.action.Action;
 import me.filoghost.chestcommands.menu.icon.AdvancedIcon;
+import me.filoghost.chestcommands.util.Utils;
 
 public class AdvancedIconMenu extends BaseIconMenu<AdvancedIcon> {
 
@@ -45,12 +46,8 @@ public class AdvancedIconMenu extends BaseIconMenu<AdvancedIcon> {
 		return fileName;
 	}
 
-	public List<Action> getOpenActions() {
-		return openActions;
-	}
-
 	public void setOpenActions(List<Action> openAction) {
-		this.openActions = openAction;
+		this.openActions = Utils.nullableCopy(openAction);
 	}
 
 	public String getPermission() {

Plugin/src/main/java/me/filoghost/chestcommands/menu/icon/AdvancedIcon.java

@@ -19,8 +19,6 @@ import java.util.List;
 import org.bukkit.entity.Player;
 import org.bukkit.inventory.Inventory;
 
-import com.google.common.collect.ImmutableList;
-
 import me.filoghost.chestcommands.action.Action;
 import me.filoghost.chestcommands.action.OpenMenuAction;
 import me.filoghost.chestcommands.api.impl.ConfigurableIconImpl;
@@ -84,7 +82,7 @@ public class AdvancedIcon extends ConfigurableIconImpl {
 	}
 
 	public void setClickActions(List<Action> clickActions) {
-		this.clickActions = ImmutableList.copyOf(clickActions);
+		this.clickActions = Utils.nullableCopy(clickActions);
 	}
 
 	@Override

Plugin/src/main/java/me/filoghost/chestcommands/menu/settings/MenuSettings.java

@@ -15,7 +15,6 @@
 package me.filoghost.chestcommands.menu.settings;
 
 import me.filoghost.chestcommands.action.Action;
-import me.filoghost.chestcommands.util.Utils;
 
 import java.util.List;
 
@@ -45,10 +44,6 @@ public class MenuSettings {
 		return rows;
 	}
 
-	public boolean hasCommands() {
-		return !Utils.isNullOrEmpty(commands);
-	}
-
 	public void setCommands(List<String> commands) {
 		this.commands = commands;
 	}

Plugin/src/main/java/me/filoghost/chestcommands/util/Utils.java

@@ -14,7 +14,11 @@
  */
 package me.filoghost.chestcommands.util;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 public final class Utils {
 
@@ -33,4 +37,20 @@ public final class Utils {
 		return collection == null || collection.isEmpty();
 	}
 
+	public static <E> List<E> nullableCopy(List<E> list) {
+		if (isNullOrEmpty(list)) {
+			return null;
+		} else {
+			return new ArrayList<>(list);
+		}
+	}
+	
+	public static <K, V> Map<K, V> nullableCopy(Map<K, V> map) {
+		if (map == null || map.isEmpty()) {
+			return null;
+		} else {
+			return new HashMap<>(map);
+		}
+	}
+
 }