Java 8: Key Features and Functional Programming Enhancements

Java 8 (also known as JDK 1.8) represents a significant release in the evolution of the Java programming language. Released by Oracle on March 18, 2014, this version introduced functional programming capabilities, a new JavaScript engine, an enhanced date-time API, and the Stream API among other innovations.

Major New Features

The Java 8 release introduced numerous enhancements, with the most notable being:

• Lambda Expressions - Enable functional programming by allowing functions to be passed as method parameters.
• Method References - Provide a concise syntax for referencing existing methods or constructors from Java classes or objects.
• Default Methods - Allow interfaces to contain method implementations alongside abstract methods.
• New Development Tools - Include the Nashorn JavaScript engine (jjs) and the class dependency analyzer (jdeps).
• Stream API - A new java.util.stream package that brings functional programming paradigms to Java collections.
• Date Time API - Enhanced API for improved date and time manipulation.
• Optional Class - A new container object that may or may not contain non-null values, designed to reduce NullPointerException occurrences.
• Nashorn JavaScript Engine - A new engine that allows JavaScript applications to run on the Java Virtual Machine.

For a comprehensive list of all enhancements, refer to the official documentation: What's New in JDK 8

To verify your Java version, use the following command:

$ java -version
java version "1.8.0_31"
Java(TM) SE Runtime Environment (build 1.8.0_31-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.31-b07, mixed mode)

Programming Paradigm Shift

Java 8 introduced a new programming paradigm that distinguishes it from Java 7. The following example demonstrates the difference in syntax between Java 7 and Java 8 approaches to sorting a collection:

import java.util.Collections;
import java.util.List;
import java.util.ArrayList;
import java.util.Comparator;

public class CollectionComparator {
   public static void main(String args[]){
   
      List<String> products1 = new ArrayList<String>();
      products1.add("Laptop ");
      products1.add("Smartphone ");
      products1.add("Tablet ");
      products1.add("Monitor ");
      products1.add("Keyboard ");
		
      List<String> products2 = new ArrayList<String>();
      products2.add("Laptop ");
      products2.add("Smartphone ");
      products2.add("Tablet ");
      products2.add("Monitor ");
      products2.add("Keyboard ");
		
      CollectionComparator comparator = new CollectionComparator();
      System.out.println("Sorted using Java 7 approach: ");
		
      comparator.sortUsingLegacyApproach(products1);
      System.out.println(products1);
      System.out.println("Sorted using Java 8 approach: ");
		
      comparator.sortUsingModernApproach(products2);
      System.out.println(products2);
   }
   
   // Traditional Java 7 sorting approach
   private void sortUsingLegacyApproach(List<String> items){   
      Collections.sort(items, new Comparator<String>() {
         @Override
         public int compare(String item1, String item2) {
            return item1.compareTo(item2);
         }
      });
   }
   
   // Java 8 functional approach
   private void sortUsingModernApproach(List<String> items){
      Collections.sort(items, (item1, item2) -> item1.compareTo(item2));
   }
}

Executing this code produces the following output:

$ javac CollectionComparator.java
$ java CollectionComparator
Sorted using Java 7 approach: 
[Keyboard , Laptop , Monitor , Smartphone , Tablet ]
Sorted using Java 8 approach: 
[Keyboard , Laptop , Monitor , Smartphone , Tablet ]

Detailed Feature Exploration

The following table outlines the key features that will be explored in detail: