🎓 Top 15 Udemy Courses (80-90% Discount): My Udemy Courses - Ramesh Fadatare — All my Udemy courses are real-time and project oriented courses.
▶️ Subscribe to My YouTube Channel (178K+ subscribers): Java Guides on YouTube
▶️ For AI, ChatGPT, Web, Tech, and Generative AI, subscribe to another channel: Ramesh Fadatare on YouTube
The Collectors class in Java is a part of the Java Stream API, which provides a set of useful methods for performing mutable reduction operations on streams of elements. Collectors are primarily used with the Stream.collect method to accumulate elements into collections, calculate summary statistics, or perform other types of reduction operations.
This guide covers various methods available in the Collectors class. Each method is described in simple terms to help beginners understand how to use them. These methods enable a wide range of operations on streams, making it a powerful tool for handling collections and stream data in Java.
For more detailed information, please refer to the official Java SE Documentation. Additional resources and tutorials can provide deeper insights into practical applications of these methods.
Java Collectors Interface Methods
The table below contains various methods of the Java Collectors interface, each with a link to a detailed explanation, examples, and real-world uses. Click on the method names to learn more about how to use them effectively in your applications.
| Method | Description |
|---|---|
| counting() | Returns a Collector that counts the number of input elements. |
| averagingInt() | Returns a Collector that calculates the arithmetic mean of integer values. |
| collectingAndThen() | Adapts a Collector to perform an additional finishing transformation. |
| filtering() | Returns a Collector that applies a filtering function to input elements before accumulation. |
| flatMapping() | Returns a Collector that performs a flat-mapping operation on input elements. |
| groupingBy() | Returns a Collector that groups elements by a classifier function. |
| groupingByConcurrent() | Returns a concurrent Collector that groups elements by a classifier function. |
| joining() | Returns a Collector that concatenates the input elements into a String. |
| mapping() | Returns a Collector that applies a mapping function to input elements before accumulation. |
| maxBy() | Returns a Collector that produces the maximal element according to a given comparator. |
| minBy() | Returns a Collector that produces the minimal element according to a given comparator. |
| partitioningBy() | Returns a Collector that partitions the input elements according to a predicate. |
| reducing() | Returns a Collector that performs a reduction on the input elements. |
| summarizingDouble() | Returns a Collector that produces a summary of double values. |
| summarizingInt() | Returns a Collector that produces a summary of integer values. |
| summingDouble() | Returns a Collector that sums double values. |
| summingLong() | Returns a Collector that sums long values. |
| teeing() | Returns a Collector that merges the results of two other Collectors. |
| toCollection() | Returns a Collector that accumulates the input elements into a new collection. |
| toConcurrentMap() | Returns a concurrent Collector that accumulates elements into a ConcurrentMap. |
| toList() | Returns a Collector that accumulates the input elements into a List. |
| toMap() | Returns a Collector that accumulates elements into a Map. |
| toSet() | Returns a Collector that accumulates the input elements into a Set. |
| toUnmodifiableList() | Returns a Collector that accumulates elements into an unmodifiable List. |
| toUnmodifiableMap() | Returns a Collector that accumulates elements into an unmodifiable Map. |
| toUnmodifiableSet() | Returns a Collector that accumulates elements into an unmodifiable Set. |
References:
My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:
Build REST APIs with Spring Boot 4, Spring Security 7, and JWT
![[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25](https://img-c.udemycdn.com/course/750x422/6852721_b512_2.jpg "[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25")
[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25
ChatGPT + Generative AI + Prompt Engineering for Beginners
Spring 7 and Spring Boot 4 for Beginners (Includes 8 Projects)
Available in Udemy for Business
Building Real-Time REST APIs with Spring Boot - Blog App
Available in Udemy for Business
Building Microservices with Spring Boot and Spring Cloud
Available in Udemy for Business
Java Full-Stack Developer Course with Spring Boot and React JS
Available in Udemy for Business
Build 5 Spring Boot Projects with Java: Line-by-Line Coding
Testing Spring Boot Application with JUnit and Mockito
Available in Udemy for Business
Spring Boot Thymeleaf Real-Time Web Application - Blog App
Available in Udemy for Business
Master Spring Data JPA with Hibernate
Available in Udemy for Business
Spring Boot + Apache Kafka Course - The Practical Guide
Available in Udemy for Business
Comments
Post a Comment
Leave Comment