Gain insights into Java 8's new features: lambdas, Stream API, Functional Interfaces, Collections improvements, Memory Management, and Date & Time API to enhance productivity and code quality.

Java 8 has introduced a ton of features and enhancements to boost developer productivity, while making your code faster, more concise, and more readable. 
In this course, you will learn about lambdas, Java Stream API, Functional Interfaces, as well as lots of other new improvements related to Collections, Memory Management, Date & Time API. 
After completing this course, you’ll be well versed in all the functionality of Java 8 and be ready to utilize these new features in your own code.

Java 8 for Experienced Developers: Lambdas, Stream API & Beyond

# Grouping operations
Grouping operations are one of the most important features of streams because they can help you complete a task, which otherwise would have taken a lot of coding, in just 2-3 lines of code.

Let's say, for example, we have a list of `Employee` objects. We need to group all our employees based on their countries of residence.
Or, say we need to find the average age/salary of all employees in a particular country.
These kinds of operations can be done very easily with grouping APIs provided in the `Collectors` class.

Let's explore these APIs in detail.

# 1) `Collectors.groupingBy()`

This method groups the input elements according to the supplied classifier and returns the results in a `Map`.

This method is similar to the group by clause of SQL, which can group data on some parameters.

There are three overloaded versions of this method. We will discuss each one of them.

## a)  `groupingBy(Function<? super T, ? extends K> classifier)`

This method takes only an instance of a `Function` interface as a parameter.

In the below example, we use `groupingby()` to group the `Employee` objects based on countries of residence.

In this lesson, we will look at the grouping operations that can be performed through the APIs provided in the Collectors class.

Let's Begin

Taste of lambdas

Stream API

Java 8 Collections Improvements

Java 8 Concurrency API Improvements

Java Time API

Conclusion

Collectors: Grouping Operations

Grouping operations

1) `Collectors.groupingBy()`

Collectors: Grouping Operations

Grouping operations

1) Collectors.groupingBy()

1) `Collectors.groupingBy()`