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I. All way to create Stream in Java 8

Way to create stream	Template	Example

1. Classic: Create stream from collection | collection.stream() | Collection<String> collection = Arrays.asList("a1", "a2", "a3");
   Stream<String> streamFromCollection = collection.stream();
2. Create stream from values | Stream.of(value1,… ,valueN) | Stream<String> streamFromValues = Stream.of("a1", "a2", "a3");
3. Create stream from array | Arrays.stream(array) | String[] array = {"a1","a2","a3"};
   Stream<String> streamFromArrays = Arrays.stream(array);
4. Create stream from part of array | Arrays.stream(array, start, end) | String[] array = {"a1","a2","a3"}; Stream<String> streamFromArrays = Arrays.stream(array, 1, 2);
5. Create stream from file (every row from file become element of stream) | Files.lines(file_path) | Stream<String> streamFromFiles = Files.lines(Paths.get("file.txt"));
6. Create stream from stirng (every char become element of stream) | "string".chars() | IntStream streamFromString = "123".chars();
7. Using Stream.builder | Stream.builder().add(...)....build() | Stream.builder().add("a1").add("a2").add("a3").build();
8. Create parallel stream from collection | collection.parallelStream() | Stream<String> stream = collection.parallelStream();
9. Create infinive strean using Stream.iterate | Stream.iterate(init_value, generate_expression) | Stream<Integer> streamFromIterate = Stream.iterate(1, n -> n 1);
10. Create infinive strean using Stream.generate | Stream.generate(generate_expression) | Stream<String> streamFromGenerate = Stream.generate(() -> "a1");
11. Create stream from path | Files.list(file_path) | Stream<Path> streamFromPath = Files.list(Paths.get(""));
12. Create stream from finding files | Files.find(file_path, max_depth, mathcher) | Stream<Path> streamFromFind = Files.find(Paths.get(""), 10, (p,a) -> true);
13. Create stream from files tree | Files.walk(file_path) | Stream<Path> streamFromFileTree = Files.walk(Paths.get(""));
14. Create stream from all entities of jar file | new JarFile(jar_file).stream() | …
15. Create stream from all entities of zip file | new ZipFile(zip_file).stream() | …
16. Create stream from iterator | StreamSupport.stream(Spliterators. spliteratorUnknownSize(iterator, 0), false) | ...
17. Create stream from iterable | StreamSupport.stream(iterable.spliterator(), false) | …
18. Create infinive stream from iterator | Stream.generate(iterator::next) | …
19. Create empty stream | Stream.empty() | Stream<String> streamEmpty = Stream.empty();
20. Create stream from Pattern | Pattern.compile(reg_exp).splitAsStream(string) | Stream<String> streamFromPattern = Pattern.compile(":").splitAsStream("a1:a2:a3");
21. Create stream from BufferedReader | bufferedReader.lines() | Stream<String> streamFromBufferedReader = bufferedReader.lines();
22. Create stream from Enum | EnumSet.allOf(MyEnum.class).stream() | Stream<MyEnum> streamFromEnum = EnumSet.allOf(MyEnum.class).stream();

II. Using filter, findFirst, findAny, skip, limit и count

Collection: Arrays.asList("a1", "a2", "a3", "a1")

Task	Example	Result
Return count the number of occurrences "a1"	collection.stream().filter("a1"::equals).count()	2
Return first element of collection or "0", if collection is empty	collection.stream().findFirst().orElse(0)	a1
Return last element of collection or "empty", if collection is empty	collection.stream().skip(collection.size() - 1).findAny().orElse("empty")	a1
Find element == "a3" or throws exeption	collection.stream().filter("a3"::equals).findFirst().get()	a3
Return the third element from collection	collection.stream().skip(2).findFirst().get()	a3
Return two elements starting from second	collection.stream().skip(1).limit(2).toArray()	[a2, a3]
Return all elements according template	collection.stream().filter((s) -> s.contains("1")).collect(Collectors.toList())	[a1, a1]