Java's I/O streams provide standardized ways to read and write data. Any object representing a mutable data source in Java exposes methods for reading and writing its data as a stream.

Q: I’ve been asked to extend my company’s Java-based spreadsheet software to read and write Excel spreadsheets. Can you recommend an open source Java library that will help me with this task?

Fedorova measured sequential and random read speeds in block sizes of 4KB, 8KB, and 16KB in each case to compare file manipulation speeds with normal system calls and mmap. And that.