Java Streams Explained Clearly (Java 8–21): Intermediate, Terminal, Lazy Execution, Stateless vs Stateful, and takeWhile() / dropWhile() Java Streams are one of the most important features introduced in Java 8 , and they are now used heavily in real-world backend projects and Java interviews . In this article, you will learn Java Streams from the ground up , including: What Java Streams are and why they exist Intermediate vs Terminal operations Why streams are lazy Stateless vs Stateful operations (very important) takeWhile() and dropWhile() explained in detail (Java 9+) Performance and parallel streams Common mistakes and interview questions This guide is written in simple language , with clear examples , and is suitable for beginners, working professionals, and interview preparation . What Are Java Streams and Why Were They Introduced? Before Java 8, most data processing in Java was done using lo...