Java 8 Features

Java 8 is a major release of the Java programming language that was first released in March 2014. It brings several new features and improvements to the Java language and platform, making it easier for developers to write high-performance, maintainable code. In this blog post, we will take a look at some of the most important features of Java 8 and how they can be used to improve your Java development experience.

1. Lambda Expressions

One of the most talked-about features of Java 8 is the introduction of lambda expressions. Lambda expressions are a way to write anonymous functions (functions without a name) that can be passed as arguments to other functions or used as expressions. This makes it easier to write functional-style code in Java, and can help to reduce boilerplate code and improve code readability.

Lambda - Is an anonymous function without name, return type and modifiers
Function<Integre,Integer> f=i->i*i;
//Provide function input n output >> Given value i, return i square
Predicate<Integer>p=i->i%2==0
//Returns true or false
(a, b)-> System.out.println(a+b);
(n)->n*n;
- java.util.function contains various functional exp for lambda

2. Functional Interfaces

In order to use lambda expressions, Java 8 also introduces the concept of functional interfaces. A functional interface is an interface that has only one abstract method. This allows developers to easily define and use lambda expressions, as the compiler can automatically infer the type of the lambda expression based on the functional interface it is being passed to.

Person p=new Person(){  
  void eat(){
	  System.out.println("nice fruits");
	  }
  };  
  p.eat();  
 
/**
Lambda Expressions --> How it Can be used in case of Functional Interfaces?
(Interface with Single Abstract Method)
**/

Drawable d2=()-> System.out.println("Drawing "+width);   
d2.draw();  
Sayable s2= name ->{  
            return "Hello, "+name;  
        };  
        
s2.name();
Addable ad2=(int a,int b)->(a+b);
Addable ad2=(int a,int b)->{return (a+b);};  
System.out.println(ad2.add(100,200));  
List.forEach(m -> System.out.println(m));  

3. The Stream API

The Stream API is a new feature of Java 8 that makes it easy to work with collections of data in a functional style. Streams allow developers to perform operations on collections of data (such as filtering, mapping, and reducing) without modifying the underlying data. This can make code more readable and maintainable, and can also lead to performance improvements.

4. The Date and Time API

Java 8 introduces a new Date and Time API, which makes it easier to work with dates and times in Java. The new API is more expressive, more intuitive, and more powerful than the previous date and time classes. It also provides built-in support for working with time zones, daylight saving time, and leap seconds.

5. Default Method in Interface

Java 8 also introduces the ability to include default methods in interfaces. This allows interfaces to have implementations of methods, so that classes that implement these interfaces don't have to provide their own implementation. This feature helps in extending the functionality of existing interfaces without breaking the classes that already implement them.

6. Concurrent Accumulators

Java 8 includes several new concurrent accumulators, which are special classes that can be used to perform operations on data in parallel. These accumulators can be used to perform operations such as counting, summing, and averaging, and can be used with both parallel and non-parallel streams.

7. Optional Class

The Optional class is a container class in Java 8 that is used to represent the presence or absence of a value. It is part of the java.util package and was introduced as a way to handle null values more safely and clearly.

An Optional object can be either empty, meaning it does not contain a value, or it can contain a non-null value. This makes it useful for situations where a method may return a null value, but the developer wants to explicitly handle the case of no value being present.

The main methods available in the Optional class include:

• isPresent(): Returns true if the Optional contains a value, false otherwise.
• get(): Returns the value contained in the Optional, or throws a NoSuchElementException if the Optional is empty.
• orElse(T other): Returns the value contained in the Optional if it is present, or returns the provided default value otherwise.
• ifPresent(Consumer<T> consumer): Executes the provided Consumer function if the Optional contains a value.

// Java program with Optional Class
import java.util.Optional;  
public class OptionalDemo{  
    public static void main(String[] args) {  
        String[] words = new String[10];  
        Optional<String> checkNull = 
                      Optional.ofNullable(words[5]);  
        if (checkNull.isPresent()) {  
            String word = words[5].toLowerCase();  
            System.out.print(word);  
        } else  
            System.out.println("word is null");  
    }  
}  

By using Optional class, the code can be more readable and understandable, as it makes it clear when a method may return a null value and how that value should be handled.

In conclusion, Java 8 brings a host of new features and improvements to the Java programming language and platform. From Lambda expressions, Functional Interfaces, Stream API, Date and Time API, Default Method in Interface, and Concurrent Accumulators, these features make it easier for developers to write high-performance, maintainable code. As a developer, it's worth exploring these features, and seeing how they can be used to improve your Java development experience.