NOTE
java.nio.file.Files
High-level Java filesystem operations and important caveats around atomicity, metadata, and large files.
This is a historical learning note and may contain outdated or incomplete understanding.
Files provides high-level helpers for file read/write, copy/move, metadata, directory traversal, symbolic links, and opening streams/channels.
Convenience methods such as readAllBytes are appropriate only when the input comfortably fits memory. Stream/channel APIs are safer for large files.
Options such as atomic move are conditional on filesystem support. A successful Java call also does not necessarily imply durable persistence to physical media unless the required force/fsync semantics are used.