Solved NBTTagCompound error

Hello people, I'm receiving a null pointer exception when trying to get the NBTTagCompound from a CraftItemStack.
Here's the error:

Code:

Caused by: java.lang.NullPointerException
        at com.marcus.test.objects.Books.getItemStack(Books.ja
va:40) ~[?:?]

Here's the method:

Code:

public ItemStack getItemStack() {
ItemStack itemStack = new ItemStack(Material.WRITTEN_BOOK);
CraftItemStack book = getCraftVersion(itemStack);
net.minecraft.server.v1_7_R4.ItemStack nmsCopy = CraftItemStack.asNMSCopy(book);
NBTTagCompound tags = nmsCopy.getTag();
 
NBTTagList nPages = new NBTTagList();
int i = 0;
for (Page page: pages) {
String[] derp = page.getPage();
nPages.add(new NBTTagString(derp[i]));
i++;
}
 
tags.setString("title", "Great banter"); // THIS IS LINE 40
tags.setString("author", "Sheep");
tags.set("pages", nPages);
 
nmsCopy.setTag(tags);
book.setAmount(1);
 
return (ItemStack) book;
}

Thanks in advance c:

Bump?

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

InfamousSheep
Why are you not using BookMeta?

 

Yeah I am now, I fixed it. I thought I was receiving the "Invalid book tag" error from using BookMeta so I decided to use NBT. It's old code I recoding XD