Introduction to the key features introduced in Java 8

Category : Java | Sub Category : Java8 Features | By Prasad Bonam Last updated: 2023-11-13 04:06:03 Viewed : 679

Introduction to the key features introduced in Java 8:

Java 8, released in March 2014, introduced several major features and enhancements to the Java programming language. Here is an overview of the key features introduced in Java 8:

1. Lambda Expressions:

   • Purpose: Lambda expressions provide a concise way to express instances of single-method interfaces (functional interfaces).
   • Syntax: (parameters) -> expression or (parameters) -> { statements }.
   • Example:

     javaCopy code
     // Old way using anonymous inner class
     Runnable oldRunnable = new Runnable() {
         @Override
         public void run() {
             System.out.println("Old way");
         }
     };
     
     // Using lambda expression
     Runnable newRunnable = () -> System.out.println("Lambda way");
     

2. Functional Interfaces:

   • Purpose: Functional interfaces are interfaces that have exactly one abstract method. They are a key enabler for lambda expressions.
   • Example:

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     @FunctionalInterface
     interface MyFunctionalInterface {
         void myMethod();
     }
     

3. Stream API:

   • Purpose: The Stream API introduces a new abstraction for working with sequences of data, allowing for concise and expressive operations on data collections.
   • Example:

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     List<String> myList = Arrays.asList("a1", "a2", "b1", "c2", "c1");
     
     myList
         .stream()
         .filter(s -> s.startsWith("c"))
         .map(String::toUpperCase)
         .sorted()
         .forEach(System.out::println);
     

4. Default Methods:

   • Purpose: Default methods allow interfaces to have method implementations, enabling backward compatibility when new methods are added to interfaces.
   • Example:

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     interface MyInterface {
         void myMethod();
     
         default void myDefaultMethod() {
             System.out.println("Default implementation");
         }
     }
     

5. Method References:

   • Purpose: Method references provide a shorthand syntax for lambda expressions, making the code more readable.
   • Example:

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     // Using lambda expression
     list.forEach(s -> System.out.println(s));
     
     // Using method reference
     list.forEach(System.out::println);
     

6. Optional:

   • Purpose: The Optional class is introduced to provide a more robust way of dealing with potentially null values, reducing the chances of NullPointerException.
   • Example:

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     Optional<String> optional = Optional.ofNullable(getValue());
     System.out.println(optional.orElse("Default Value"));
     

7. New Date and Time API:

   • Purpose: The java.time package provides a comprehensive set of classes for date and time manipulation, addressing the limitations of the older java.util.Date and java.util.Calendar.
   • Example:

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     LocalDate today = LocalDate.now();
     

8. CompletableFuture:

   • Purpose: CompletableFuture is introduced for asynchronous programming. It represents a promise that can be completed with a value or exception in the future.
   • Example:

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     CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
         // Asynchronous task
     });
     

9. Nashorn JavaScript Engine:

   • Purpose: The Nashorn JavaScript engine is included, providing a lightweight and high-performance JavaScript runtime for Java applications.
   • Example:

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     ScriptEngineManager manager = new ScriptEngineManager();
     ScriptEngine engine = manager.getEngineByName("nashorn");
     engine.eval("print(`Hello, Nashorn!`)");
     

These features collectively brought significant improvements to the Java language, making it more expressive, concise, and capable of handling modern programming paradigms. Java 8`s features laid the foundation for subsequent releases, influencing the direction of Java`s evolution.