Fix behavior of itemdb command on legacy versions (#4320)

Essentials/src/main/java/com/earth2me/essentials/commands/Commanditemdb.java

@@ -7,6 +7,7 @@ import org.bukkit.Material;
 import org.bukkit.Server;
 import org.bukkit.inventory.ItemStack;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
@@ -55,9 +56,13 @@ public class Commanditemdb extends EssentialsCommand {
         }
 
         List<String> nameList = ess.getItemDb().nameList(itemStack);
+        nameList = nameList != null ? new ArrayList<>(nameList) : new ArrayList<>();
         nameList.addAll(ess.getCustomItemResolver().getAliasesFor(ess.getItemDb().name(itemStack)));
-        Collections.sort(nameList);
+        if (nameList.isEmpty()) {
+            return;
+        }
 
+        Collections.sort(nameList);
         if (nameList.size() > 15) {
             nameList = nameList.subList(0, 14);
         }

Essentials/src/main/java/com/earth2me/essentials/items/CustomItemResolver.java

@@ -44,11 +44,13 @@ public class CustomItemResolver implements IItemDb.ItemResolver, IConf {
 
     public List<String> getAliasesFor(String item) throws Exception {
         final List<String> results = new ArrayList<>();
+        if (item != null) {
             for (Map.Entry<String, String> entry : map.entrySet()) {
                 if (item.equalsIgnoreCase(ess.getItemDb().name(ess.getItemDb().get(entry.getValue())))) {
                     results.add(entry.getKey());
                 }
             }
+        }
         return results;
     }
 

Essentials/src/main/resources/items.csv

@@ -7490,6 +7490,9 @@ sparklymelon,382,0
 shiningmelon,382,0
 gmelon,382,0
 smelon,382,0
+mobegg,383,0
+spawnegg,383,0
+mobspawnegg,383,0
 creeperegg,383,50
 eggcreeper,383,50
 skeletonegg,383,51