Dinesh on Java

Java 8 is a revolutionary release of the world’s no.1 development platform. Java 8 is a massive upgrade from the previous Java programming model. It is an enhanced, coordinated advancement of the previously available JVM, Java language, and libraries.

New Added Features in Java 8

Java 8 includes improved features along with a set of new interesting features. The Java 8 features include methods for productivity, ease of use, improved polyglot programming, better security. And Java 8 overall improved performance that is definitely going to leave an impression. Java 8 is the latest iteration of the largest, standards-based, community-driven platform.

In this article, let’s take a look at some of Java 8’s most stunning and interesting new features.

Interface Default and Static Methods

Prior to the release of Java 8, interfaces could only abstract public methods. You couldn’t add new functions to an existing interface without causing a ripple in all implementing classes and ensure they have created an implementation of the new methods.

Java 8 revolutionizes things. Interfaces can now have static and default methods that possess a defined behavior. Let’s take a look at what these features entail.

Static Method

Consider the following method of an interface:

static String producer() {
    return "N&F Vehicles";
}

The static method is only available through and inside an interface. It can’t be overridden by an implementing class.
To call it outside an interface:

String producer = Vehicle.producer()

Default Method

Default methods are now accessible through the instance of the implementing class and can be overridden. Let’s add a default method to our interface:

default String getOverview() {
    return "ATV made by " + producer();
}

This class should be created to execute the default method in Java 8.

Vehicle vehicle = new VehicleImpl();
String overview = vehicle.getOverview();

Lambda Expression

Lambda expression is considered pretty popular among the coders who have expertise in programming languages like Scala. However, in Java codes. A Lambda expression is simply an anonymous function that doesn’t have a name and is not tied to an identifier. They are typically used as a parameter to an outside function.

Here’s a sample syntax:

either

(parameters) -> expression

or

(parameters) -> { statements; }

or

() -> expression

A conventional Lambda expression looks as follows:

(x, y) -> x + y  //Two parameters are entered in this function and it displays them as the result.

PRE-REQUISITES OF LAMBDA EXPRESSIONS

• A lambda expression usually consists of expressions ranging from zero to two.
• Sometimes the type or parameters are explicitly stated, other times the user has to infer them.
• Multiple parameters may bound by parentheses and commas are utilized to separate them. A null parameter is represented by empty parentheses.
• The use of parentheses is not necessary in case of one parameter with its type inferred. e.g. a -> return a*a.
• Similar to the parameters, the main section (body) of a lambda expression can have zero or more statements.
• Curly brackets are not required if the body of the Lambda expression consists of only a single statement. Also, body expression and anonymous function must have the same return type. Curly brackets are mandatory in case of multiple statements in a body.

Functional Interface

Functional interfaces in other words termed as single Abstract Method interfaces. As the name itself suggests, they allow just a single method inside. Java 8 launches an annotation – @FuntionalInterface this is useful for errors on compiler level.

Following is an example of Functional Interface:

@FunctionalInterface
public interface MyFirstFunctionalInterface {
    public void firstWork();
}

Consider the function interface’s valid even when @FunctionalInterface is eliminated. It only serves as a reminder so that compiler enforces the only abstract method within it. The default methods are not considered abstract you can add as many default methods to you Functional Interface as you like.

Below is an example of a Functional Interface:

@FunctionalInterface
public interface MyFirstFunctionalInterface
{
    public void firstWork();
 
    @Override
    public String toString();                //Overridden from Object class
 
    @Override
    public boolean equals(Object obj);        //Overridden from Object class
}

Streams

Java 8 introduced another major feature called Java 8 Streams API. It provides a medium for setting a set of data in many ways that are filtering, transformation, or any other useful process.

The Streams API feature in Java 8 supports is various categories of iteration.  In which you can define a group of items waiting to function, the operations to be on every item and the storage of the output.

An example of stream API is as follows:

List items;
String prefix;
List filteredList = items.stream().filter(e -> (!e.startsWith(prefix))).collect(Collectors.toList());

OPTIONAL

An optional feature has revolutionized the efficiency of Java 8 by a milestone. Before the release of this, the Java 8 developers have to meticulously check and validate the values they referred to because there was a huge possibility of throwing the NullPointerException (NPE). All these checks took not only plenty of time but also demanded a pretty frustrating and error-prone boilerplate code.

Java 8 Optional class can help handle and rectify a number of situations where there’s even the slightest chance of getting the NPE. It acts as a container for the object of type T. It can return the value of this object if it isn’t null. When the value inside this container is null, it allows the operation of a procedure that could work around the error to find a solution instead of imposing the NPE.

Conclusion

In a lot of cases, Java 8 has improved application performance and revolutionized the Java programme. Lambda expressions, the Streams API, Default Methods, and a variety of different methods on existing classes are some of the key improvements in Java 8. Java 8’s new Optional Type gives developers enough flexibility to deal with null values, reducing the likelihood of NullPointerExceptions.