PaperMC/nms-patches/EntityProjectileThrowable.patch

--- a/net/minecraft/server/EntityProjectileThrowable.java
+++ b/net/minecraft/server/EntityProjectileThrowable.java
@@ -18,8 +18,8 @@
 
     public void setItem(ItemStack itemstack) {
         if (itemstack.getItem() != this.i() || itemstack.hasTag()) {
-            this.getDataWatcher().set(EntityProjectileThrowable.e, SystemUtils.a((Object) itemstack.cloneItemStack(), (itemstack1) -> {
-                itemstack1.setCount(1);
+            this.getDataWatcher().set(EntityProjectileThrowable.e, SystemUtils.a(itemstack.cloneItemStack(), (itemstack1) -> { // CraftBukkit - decompile error
+                if (!itemstack1.isEmpty()) itemstack1.setCount(1); // CraftBukkit
             }));
         }
 
@@ -27,7 +27,13 @@
 
     protected abstract Item i();
 
-    protected ItemStack getItem() {
+    // CraftBukkit start
+    public Item getDefaultItem() {
+        return i();
+    }
+    // CraftBukkit end
+
+    public ItemStack getItem() { // PAIL protected -> public
         return (ItemStack) this.getDataWatcher().get(EntityProjectileThrowable.e);
     }