Stream hack in Java8

Stream is a new feature added to java8 that allows elements in a collection to be called in a pipelined fashion. If only the method calls Stream’s method as its return type. It’s a superficial assembly line, not black technology. Compare the expected results of the following code with the actual results.

Stream<String> strs = Stream.generate(() -> "A").limit(3);
strs.map(s -> {
    System.out.println("map1");
    return s + "A";
}).map(s -> {
    System.out.println("map2");
    return s + "A";
}).map(s -> {
    System.out.println("map3");
    return s + "A";
}).forEach(System.out::println);
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Stream

map(Function
mapper). The map method is executed three times, each time returning a Stream object. Finally, the forEach method is called. The result should be

map1
map1
map1
map2
map2
map2
map3
map3
map3
AAAA
AAAA
AAAA
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The actual results were surprising:

map1
map2
map3
AAAA
map1
map2
map3
AAAA
map1
map2
map3
AAAA
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The Stream will be three timesmapCall and onceforEachThe call is optimized. Each time an element is iterated, three are executed at a timeThe map 'and onceThe forEach ` method.