--- a/net/minecraft/world/SimpleContainer.java
+++ b/net/minecraft/world/SimpleContainer.java
@@ -14,18 +14,98 @@
 import net.minecraft.world.item.Item;
 import net.minecraft.world.item.ItemStack;
 
+// CraftBukkit start
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.entity.CraftHumanEntity;
+import org.bukkit.entity.HumanEntity;
+// CraftBukkit end
+
 public class SimpleContainer implements Container, StackedContentsCompatible {
 
     private final int size;
     public final NonNullList<ItemStack> items;
     @Nullable
     private List<ContainerListener> listeners;
+
+    // CraftBukkit start - add fields and methods
+    public List<HumanEntity> transaction = new java.util.ArrayList<HumanEntity>();
+    private int maxStack = MAX_STACK;
+    protected @Nullable org.bukkit.inventory.InventoryHolder bukkitOwner; // Paper - annotation
+
+    public List<ItemStack> getContents() {
+        return this.items;
+    }
+
+    public void onOpen(CraftHumanEntity who) {
+        this.transaction.add(who);
+    }
+
+    public void onClose(CraftHumanEntity who) {
+        this.transaction.remove(who);
+    }
+
+    public List<HumanEntity> getViewers() {
+        return this.transaction;
+    }
+
+    @Override
+    public int getMaxStackSize() {
+        return this.maxStack;
+    }
+
+    public void setMaxStackSize(int i) {
+        this.maxStack = i;
+    }
+
+    public org.bukkit.inventory.InventoryHolder getOwner() {
+        // Paper start - Add missing InventoryHolders
+        if (this.bukkitOwner == null && this.bukkitOwnerCreator != null) {
+            this.bukkitOwner = this.bukkitOwnerCreator.get();
+        }
+        // Paper end - Add missing InventoryHolders
+        return this.bukkitOwner;
+    }
 
+    @Override
+    public Location getLocation() {
+        // Paper start - Fix inventories returning null Locations
+        // When the block inventory does not have a tile state that implements getLocation, e. g. composters
+        if (this.bukkitOwner instanceof org.bukkit.inventory.BlockInventoryHolder blockInventoryHolder) {
+            return blockInventoryHolder.getBlock().getLocation();
+        }
+        // When the bukkit owner is a bukkit entity, but does not implement Container itself, e. g. horses
+        if (this.bukkitOwner instanceof org.bukkit.entity.Entity entity) {
+            return entity.getLocation();
+        }
+        // Paper end - Fix inventories returning null Locations
+        return null;
+    }
+
+    public SimpleContainer(SimpleContainer original) {
+        this(original.size);
+        for (int slot = 0; slot < original.size; slot++) {
+            this.items.set(slot, original.items.get(slot).copy());
+        }
+    }
+
     public SimpleContainer(int size) {
-        this.size = size;
-        this.items = NonNullList.withSize(size, ItemStack.EMPTY);
+        this(size, null);
+    }
+    // Paper start - Add missing InventoryHolders
+    private @Nullable java.util.function.Supplier<? extends org.bukkit.inventory.InventoryHolder> bukkitOwnerCreator;
+    public SimpleContainer(java.util.function.Supplier<? extends org.bukkit.inventory.InventoryHolder> bukkitOwnerCreator, int size) {
+        this(size);
+        this.bukkitOwnerCreator = bukkitOwnerCreator;
     }
+    // Paper end - Add missing InventoryHolders
 
+    public SimpleContainer(int i, org.bukkit.inventory.InventoryHolder owner) {
+        this.bukkitOwner = owner;
+        // CraftBukkit end
+        this.size = i;
+        this.items = NonNullList.withSize(i, ItemStack.EMPTY);
+    }
+
     public SimpleContainer(ItemStack... items) {
         this.size = items.length;
         this.items = NonNullList.of(ItemStack.EMPTY, items);