The CraftBlockStateMeta constructor CraftBlockStateMeta(Map) invokes its
parent constructor, which itself invokes deserializeInternal, which is
implemented on CraftBlockStateMeta to read the components and block
entity tag from the passed map.
Field initialization happens after the call to the super constructor,
meaning the current code overwrites the parsed internal data with the
EMPTY defaults.
This is prevented by moving the initialization into its own code block
that can null check the fields prior to defaulting their value to EMPTY.