The setTagInfo() function.

Thank you. I am only down to 1 error. I am using... 

				Map<Integer, String> wordsByKey = new HashMap<>();
				wordsByKey.put(1, "one");
				wordsByKey.put(2, "two");
				wordsByKey.put(3, "three");
				wordsByKey.put(4, "four");
				(new Object() {
					public ItemStack getItemStack(BlockPos pos, int sltid) {
						AtomicReference<ItemStack> _retval = new AtomicReference<>(ItemStack.EMPTY);
						TileEntity _ent = world.getTileEntity(pos);
						if (_ent != null) {
							_ent.getCapability(CapabilityItemHandler.ITEM_HANDLER_CAPABILITY, null).ifPresent(capability -> {
								_retval.set(capability.getStackInSlot(sltid).copy());
							});
						}
						return _retval.get();
					}
				}.getItemStack(new BlockPos((int) (x + (xval)), (int) (y + (yval)), (int) (z + (zval))), (int) (0))).setTagInfo(
						"pages",
						new CompoundNBT(wordsByKey));

and I am getting the error... 

        incompatible types: Map cannot be converted to Map new CompoundNBT(wordsByKey));

I am sending a variable of 'Map' as an argument to CompoundNBT(), but it can't seem to convert, even though they are of the same types???

I fied it... 

CompoundNBT nbtTag = new CompoundNBT();
				nbtTag.putString("author", "Michael S. Lowe");
				nbtTag.putString("title", "Scripture");
				nbtTag.putString("pages", "This is page 1.");
				(new Object() {
					public ItemStack getItemStack(BlockPos pos, int sltid) {
						AtomicReference<ItemStack> _retval = new AtomicReference<>(ItemStack.EMPTY);
						TileEntity _ent = world.getTileEntity(pos);
						if (_ent != null) {
							_ent.getCapability(CapabilityItemHandler.ITEM_HANDLER_CAPABILITY, null).ifPresent(capability -> {
								_retval.set(capability.getStackInSlot(sltid).copy());
							});
						}
						return _retval.get();
					}
				}.getItemStack(new BlockPos((int) (x + (xval)), (int) (y + (yval)), (int) (z + (zval))), (int) (0))).setTagInfo(
						"pages",
						nbtTag);

I get no errors, but my books still say, "*Invalid book tag*" in them. I don't know if it is because I am not modifying my CompoundNBT (nbtTag) variable correctly.

    All I need to do now (to finish my mod) is figure out how to set the CompoundNBT variable (value) properly and pass it on to the ItemStack.setTagInfo(java.lang.String key, NBTBase value)  function, to hopefully put the correct data into the 'written books' of my mod, and not have them all say, "*Invalid Book Tag*" when I open them in my game. 

      I Googled "CompoundNBT" for documentation, and Google thinks I am searching 2 words, "Compound NBT" even though I put it in quotes. Does anyone know how to use the CompoundNBT class variable for 'written books' in Minecraft? Thank you. I  saw an outdated code from 7 years ago...

ItemStack tomeStack = new ItemStack(Item.writableBook);
NBTTagList bookPages = new NBTTagList("pages");
bookPages.appendTag(new NBTTagString("1", "Insert text here."));
bookPages.appendTag(new NBTTagString("2", "Insert moar text here."));
tomeStack.setTagInfo("pages", bookPages);
tomeStack.setTagInfo("author", new NBTTagString("author", "Author name here"));
tomeStack.setTagInfo("title", new NBTTagString("title", "Title here"));
tomeStack.itemID = Item.writtenBook.itemID;

    ... so it shouldn't be impossible to create vanilla written books now (using CompoundNBT). 

I did Google "CompoundNBT class", and only got information on something like NBTTagCompound, which is not the class I am trying to use.

   Thank you. It is my first time working with Intellij. I downloaded it. It gives me a 30 day trial, and all I know it to do is 'create projects'. Ctrl+click seems to select multiple items I assume are in a newly created project (like it would do in File Explorer), but I am really not interested in creating new projects. I am just trying to find any kind of documentation I can find on the CompoundNBT class for assigning data to a written book. 

     In my code above, I am already using a variable of the CompactNBT class, but it seems like I am not using the variable's properties correctly because my books still say, "*Invalid Book Tag*" in them. I would just only need to know which tag(s) to set, and how.

so far,

CompoundNBT nbtTag = new CompoundNBT();
nbtTag.putString("author", "Michael S. Lowe");
nbtTag.putString("title", "Scripture");
nbtTag.putString("pages", "This is page 1.");

is not working.