What is the difference between intermediate and terminal methods in programming?

In Java, Stream API methods are divided into intermediate and terminal.

Intermediate methods return a new Stream and allow building a chain of operations. They are lazy, meaning they are not executed immediately but only when a terminal method is called. Examples: filter(), map(), sorted().

Terminal methods trigger the execution of the entire chain of operations and return a result (not a Stream). After their invocation, the Stream is considered used and cannot be reused. Examples: collect(), forEach(), reduce().

Example:

List<String> names = List.of("Anna", "Bob", "Charlie");

List<String> filtered = names.stream()  // create a Stream
    .filter(name -> name.startsWith("A"))  // intermediate method
    .map(String::toUpperCase)  // intermediate method
    .collect(Collectors.toList());  // terminal method

System.out.println(filtered); // [ANNA]