Okio is a Java I/O library providing a set of tools for efficient byte-stream processing and file system operations. It functions as a buffered byte stream handler and streaming data transformer, utilizing a cross-platform file system API to manage data movement.
The project is distinguished by its use of pooled mutable byte buffers that treat sequences as queues to reduce memory copying and garbage collection churn. It further decouples file operations from the host operating system through an abstraction-based file system, allowing for consistent path manipulation and atomic operations across Windows and Unix systems, as well as the ability to treat ZIP archives as read-only file systems.
The library covers a broad range of capabilities including cryptographic data integrity via real-time stream hashing and encryption, and data compression using Gzip and Deflate algorithms. It also provides network socket communication and in-memory file system simulation for mocking I/O operations during testing.
