Fix handling for null ContainerTypes

EnumMap does not permit null values.

core/src/main/java/org/geysermc/geyser/translator/inventory/InventoryTranslator.java

@@ -41,6 +41,7 @@ import com.nukkitx.protocol.bedrock.data.inventory.stackrequestactions.*;
 import com.nukkitx.protocol.bedrock.packet.ItemStackResponsePacket;
 import it.unimi.dsi.fastutil.ints.*;
 import lombok.AllArgsConstructor;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import org.geysermc.geyser.GeyserImpl;
 import org.geysermc.geyser.inventory.CartographyContainer;
 import org.geysermc.geyser.inventory.GeyserItemStack;
@@ -65,11 +66,8 @@ import java.util.*;
 public abstract class InventoryTranslator {
 
     public static final InventoryTranslator PLAYER_INVENTORY_TRANSLATOR = new PlayerInventoryTranslator();
-    public static final Map<ContainerType, InventoryTranslator> INVENTORY_TRANSLATORS = new EnumMap<>(ContainerType.class) {
+    private static final Map<ContainerType, InventoryTranslator> INVENTORY_TRANSLATORS = new EnumMap<>(ContainerType.class) {
         {
-            /* Player Inventory */
-            put(null, PLAYER_INVENTORY_TRANSLATOR);
-
             /* Chest UIs */
             put(ContainerType.GENERIC_9X1, new SingleChestInventoryTranslator(9));
             put(ContainerType.GENERIC_9X2, new SingleChestInventoryTranslator(18));
@@ -878,6 +876,22 @@ public abstract class InventoryTranslator {
         return slotInfoData.getContainer() == ContainerSlotType.CURSOR;
     }
 
+    /**
+     * Gets the {@link InventoryTranslator} for the given {@link ContainerType}.
+     * Returns {@link #PLAYER_INVENTORY_TRANSLATOR} if type is null.
+     *
+     * @param type the type
+     * @return the InventoryType for the given ContainerType.
+     */
+    @Nullable
+    public static InventoryTranslator inventoryTranslator(@Nullable ContainerType type) {
+        if (type == null) {
+            return PLAYER_INVENTORY_TRANSLATOR;
+        }
+
+        return INVENTORY_TRANSLATORS.get(type);
+    }
+
     protected enum CraftState {
         START,
         RECIPE_ID,

core/src/main/java/org/geysermc/geyser/translator/protocol/java/inventory/JavaOpenScreenTranslator.java

@@ -45,7 +45,7 @@ public class JavaOpenScreenTranslator extends PacketTranslator<ClientboundOpenSc
             return;
         }
 
-        InventoryTranslator newTranslator = InventoryTranslator.INVENTORY_TRANSLATORS.get(packet.getType());
+        InventoryTranslator newTranslator = InventoryTranslator.inventoryTranslator(packet.getType());
         Inventory openInventory = session.getOpenInventory();
         // No translator exists for this window type. Close all windows and return.
         if (newTranslator == null) {