Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()0%

Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()

Advanced16 min read•Updated: 2025-01-15

🏁 Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()

Introduction

A terminal operation triggers the evaluation of the stream pipeline and produces a non-stream result (such as a Collection, a primitive value, or a side effect like printing). Once a terminal operation is executed, the stream is closed.

🛠️ Key Terminal Operations

1. `reduce()` (Folding / Aggregation)

Combines all elements of a stream into a single summary result:

1List<Integer> numbers = List.of(10, 20, 30, 40);
2 
3// reduce(identity, BinaryOperator)
4int sum = numbers.stream().reduce(0, (a, b) -> a + b); // 100
5int product = numbers.stream().reduce(1, (a, b) -> a * b); // 240000

2. `collect(Collector)`

Gathers elements into collections like List, Set, or Map:

1Set<String> uniqueCities = citiesStream.collect(Collectors.toSet());

3. Short-Circuiting Matching Operations

These stop processing elements as soon as the outcome can be determined:

1List<String> students = List.of("Aarav", "Neha", "Deepak");
2 
3boolean anyStartsWithA = students.stream().anyMatch(s -> s.startsWith("A")); // true
4boolean allLengthGt3 = students.stream().allMatch(s -> s.length() > 3);     // true
5boolean noneStartsWithZ = students.stream().noneMatch(s -> s.startsWith("Z")); // true

4. Search Operations: `findFirst()` and `findAny()`

Return an Optional<T>:

1Optional<String> firstMatch = students.stream()
2                                      .filter(s -> s.length() > 4)
3                                      .findFirst();
4 
5firstMatch.ifPresent(name -> System.out.println("First found: " + name));

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Intermediate Operations: filter(), map(), flatMap(), sorted(), distinct()	Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

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Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()

Advanced16 min read•Updated: 2025-01-15

Study Materials

🏁 Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()

Introduction

🛠️ Key Terminal Operations

1. `reduce()` (Folding / Aggregation)

Combines all elements of a stream into a single summary result:

1List<Integer> numbers = List.of(10, 20, 30, 40);
2 
3// reduce(identity, BinaryOperator)
4int sum = numbers.stream().reduce(0, (a, b) -> a + b); // 100
5int product = numbers.stream().reduce(1, (a, b) -> a * b); // 240000

2. `collect(Collector)`

Gathers elements into collections like List, Set, or Map:

1Set<String> uniqueCities = citiesStream.collect(Collectors.toSet());

3. Short-Circuiting Matching Operations

These stop processing elements as soon as the outcome can be determined:

1List<String> students = List.of("Aarav", "Neha", "Deepak");
2 
3boolean anyStartsWithA = students.stream().anyMatch(s -> s.startsWith("A")); // true
4boolean allLengthGt3 = students.stream().allMatch(s -> s.length() > 3);     // true
5boolean noneStartsWithZ = students.stream().noneMatch(s -> s.startsWith("Z")); // true

4. Search Operations: `findFirst()` and `findAny()`

Return an Optional<T>:

1Optional<String> firstMatch = students.stream()
2                                      .filter(s -> s.length() > 4)
3                                      .findFirst();
4 
5firstMatch.ifPresent(name -> System.out.println("First found: " + name));

Next Lesson

Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

Related Lessons

Previous Lesson	Next Lesson
Intermediate Operations: filter(), map(), flatMap(), sorted(), distinct()	Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

Practice Quiz

Test your understanding of this lesson with 1 questions. Each question has one correct answer.

Previous Next

🏁 Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()

Introduction

🛠️ Key Terminal Operations

1. reduce() (Folding / Aggregation)

2. collect(Collector)

3. Short-Circuiting Matching Operations

4. Search Operations: findFirst() and findAny()

Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

Related Lessons

Practice Quiz

Loading Page Content...

🏁 Terminal Operations: collect(), forEach(), reduce(), count(), anyMatch()

Introduction

🛠️ Key Terminal Operations

1. reduce() (Folding / Aggregation)

2. collect(Collector)

3. Short-Circuiting Matching Operations

4. Search Operations: findFirst() and findAny()

Collectors Utility: groupingBy(), partitioningBy(), joining(), toList()

Related Lessons

Practice Quiz

1. `reduce()` (Folding / Aggregation)

2. `collect(Collector)`

4. Search Operations: `findFirst()` and `findAny()`

1. `reduce()` (Folding / Aggregation)

2. `collect(Collector)`

4. Search Operations: `findFirst()` and `findAny()`