The streams API was added in Java 8 to ease the task of performing bulk operations, sequentially or in parallel. This API provides two key abstractions: the stream, which represents a finite or infinite sequence of data elements, and the stream pipeline, which represents a multistage computation on these elements.
I think a great analogy, which comes from the Designing Data Intensive Applications book, is piping commands in Unix. The first command emits data elements (very often lines from a file), each command operates on the lines (such as `grep` for filtering), eventually outputting to STDOUT, file, etc..
