NIO

Non-blocking I/O

.https://docs.oracle.com/javase/8/docs/api/java/nio/package-summary.html

The central abstractions:

1. Buffers, which are containers for data

2. Charsets and their associated encoder and decoders, which translate between byte and Unicode characters

3. Channels of various types which represent connections to entities capable of performing I/O operations

4. Selectors and selection keys, which together with selection channels define a multiplexed, non-blocking I/O facility

Passing a null argument to a constructor or method in this package cause NullPointerException.