Stream<String> a = Stream.of("one", "two");
Stream<String> b = Stream.of("three", "four");
Stream.concat(a, b);
or
Stream.of(a, b, c)
.reduce(Stream::concat)
.orElseGet(Stream::empty);
or
Stream.of(a, b, c).flatMap(s -> s);
X. Ma, Z. Fu, Y. Jiang, M. Yang, and H. Stephen. International Journal of Computer Science and Information Technology (IJCSIT), 9 (3):
31 - 41(June 2017)
S. Shankar, G. Rajendra, K. Ashok, and G. Nanaso. International Journal on Recent and Innovation Trends in Computing and Communication, 3 (3):
1361--1366(March 2015)