Java 8 New Features

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Java 8  New Features:


1. Java Programming Language

    • Lambda Expressions
    • Default Methods & Static methods in Interface
    • Repeating Annotations
    • Type Annotations
    • Method Parameter Reflection
    • Method Reference
    • Improved Type inference.


2. Collections:

    • Stream package
    • Hash Map performance improvement with key collisions.


3. Date-Time Package 

4. Nashorn Javascript Engine

5. java.util.*

    • PARALLEL Arrays
    • Unsigned Arithmetic Support

6. New JDBC 4.2 API

7. Java DB 10.10

8. java.util.concurrent

    • ConcurrentHashMap to support aggregate Operations
    • atomic package to support scalable
    • ForkJoinPool to support Common Pool.
    • StampedLock to provide capability-based lock with 3 modes for controlling read/write access.


Default and Static methods in interface:


  • Before Java8 it was not possible to add new functionality to the existing interface without forcing all the implementation classes to create an implementation of new methods


  • It was forced to implement new methods to the existing implementation classes


Static in interface:

Static methods are available only inside the interface, it can’t be overridden by implementation classes.


e.g:

     interface A{


  static String newMethod(){

   return “new java8”; 

  }

}

outside calling: A.newMethod();


Default in interface:

These are accessible through instance of the implementation classes and can be overridden


e.g.:

default String getMethod(){

          return “new methods”;    

}


Method References:

It’s used for shorter and more readable alternative


 For Static Methods:

      list.stream().anyMatch(A::newMethod);

 

For Instance Methods:

      A a = new A();

    list.stream().anyMatch(a::getMethod);


   other examples

     list.stream().filter(String::isEmpty).count();

    Stream<User> stream = list.stream().map(User::new);



Repeatable annotations:




Prior to Java8, to have a repeated annotation, will have to group them in a container annotation


@Manufactures({

@Manufacturer(name =”BMW”),

@Manufacturer(name = “Range Rover”)})

public class Car{

//code goes in here

}


With java8 we can do that without container annotations


@Manufacturer(name = “BMW”)

@Manufacturer(name= “Range Rover”)

public class Car{

//code goes in here

}

 Java compiles this time around takes responsibility for wrapping two annotations into a container







Reference 

https://github.com/winterbe/java8-tutorial























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