Optional class in java 8

The Optional class was introduced in Java 8 as a way to handle the null values in a cleaner and more elegant way. The Optional class is a container object that can either contain a non-null value or be empty. Java8 Optional Class: The Optional class in Java is a container class that is designed to handle the presence or absence of a value. The primary purpose of the Optional class is to reduce the number of null checks in code and make it easier to write clean and concise code. Java 8 introduced the Optional class, and since then, it has been widely adopted by developers. One of the most significant benefits of using the Optional class is that it helps to eliminate NullPointerExceptions. This class provides several useful methods to handle and manipulate the values contained in an Optional object. In this article, we will take a closer look at the methods provided by the Optional class in Java and how they can be used to handle null values in a more effective way. Optional class methods: These methods allow you to manipulate the values contained in an Optional object and return a new Optional object. • of(): This method is used to create an Optional object that contains a non-null value. If the value passed to this method is null, it will throw a NullPointerException. This method is commonly used to create an Optional object from a value that is guaranteed to be non-null. • ofNullable(): This method is used to create an Optional object that can contain either a non-null va...

Java Optional Class Java introduced a new class Optional in jdk8. It is a public final class and used to deal with NullPointerException in Java application. You must import java.util package to use this class. It provides methods which are used to check the presence of value for particular variable. Java Optional Class Methods Methods Description public static Optional empty() It returns an empty Optional object. No value is present for this Optional. public static Optional of(T value) It returns an Optional with the specified present non-null value. public static Optional ofNullable(T value) It returns an Optional describing the specified value, if non-null, otherwise returns an empty Optional. public T get() If a value is present in this Optional, returns the value, otherwise throws NoSuchElementException. public boolean isPresent() It returns true if there is a value present, otherwise false. public void ifPresent(Consumer consumer) If a value is present, invoke the specified consumer with the value, otherwise do nothing. public Optional filter(Predicate predicate) If a value is present, and the value matches the given predicate, return an Optional describing the value, otherwise return an empty Optional. public Optional map(Function mapper) If a value is present, apply the provided mapping function to it, and if the result is non-null, return an Optional describing the result. Otherwise return an empty Optional. public Optional flatMap(Function mapper) If a value ...

An Optional object in Java is a container object that can hold both empty and a non-null values. If an Optional object does contain a value, we say that it is present; if it does not contain a value, we say that it is empty. In this Java programming tutorial, we will take a look at the Optional class in Java and how it can be used to help improve your code. We will also look at some of the drawbacks of using the Optional keyword in Java. Learn more about classes and objects in our Tutorial: What is the Optional Type in Java? Optional is a new type introduced in Java 8. It is used to represent a value that may or may not be present. In other words, an Optional object can either contain a non-null value (in which case it is considered present) or it can contain no value at all (in which case it is considered empty). An Optional object can have one of the following possible states: • Present: The Optional object does not represent absence. A value is in the Optional object and it can be accessed by invoking get(). • Absent: The Optional object does represent absence of a value; you cannot access its content with get(). Why Do Developers Need Optional in Java? Optional is generally used as a return type for methods that might not always have a result to return. For example, a method that looks up a user by ID might not find a match, in which case it would return an empty Optional. Optional can help to reduce the number of null pointer exceptions in your code. It is not intende...

Overview Optional class introduced in Java 8 provides a clean, better, and correct way of Java programming by forcing programmers to handle the values that could be null. Before Java 8, developers depended on if-else blocks to act on variables that might hold a null reference. Often, developers forget the check resulting in the so-called NullPointerException and the application crashes unwantedly during runtime. Scope • This article explains the Optional class. • It also describes how using Optional is different and better than not using it. • This article will discuss various methods supported by Optional through examples. What is an Optional Class in Java 8 ? Consider a situation where you want to return a list based on a condition. Let's say you want to get a list of all the individuals (living in some place in a country other than India) who are Indians. Such a list may or may not exist, i.e., in this case, value (the list of individuals) may be present or absent. When the value is absent you may use an optional value to represent its absence. You would say that null can be returned as an optional value. But by returning null via methods you are hiding the fact about the value's presence. This null reference is a source of many problems. You could call a method on it unknowingly, and as a result, your program terminates abruptly, throwing a NullPointerException. Even if you handle such cases by appropriate null checks using if-else, you would be compromising your code'...

Java 8 introduced the Optionalclass to make handling of nulls less error-prone. For example, the following program to pick the lucky name has a null check as: public static final List NAMES = Arrays.asList("Rita", "Gita", "Nita", "Ritesh", "Nitesh", "Ganesh", "Yogen", "Prateema"); public String pickLuckyNameOldWay(final List names, final String startingLetter) There are other many more methods in the Optionalclass to handle null in more proper way. You can go through the As always, if you want to look into the source code for the example presented above,they are available on

I'm trying to convert an existing snippet of code to some fancy Java 8 one-liner. private static final Map FOO_MAP = ... public static Foo getForCode(final Integer code) The behavior of returning null if the input is null, is questionable to begin with. The preferred behavior is “fail-fast” instead of letting the programmer trace backward through the program to find out, where the original null came from. When you replace Optional.ofNullable(code) with Optional.of(code) in your code, you already have the recommended behavior. Without changing the behavior of the original function, I don't think Optional buys you anything here, except the opportunity to bury some complex conditionals within its methods and lambdas. If you were to minimize the conditional expressions, using if-statements and boolean expressions, you'd end up with this: Foo getForCode(Integer code) This is a tad more readable than any solution using Optional, to my eye, though it's still pretty obscure. If you're willing to change the semantics of the function, and to return an Optional, then the @Holger I agree; I detest the "return-null-if-input-is-null" antipattern. I had actually started to write an editorial comment on that very topic, but then it started to turn into an essay, which seemed like it would be a distraction from the answer. :-) But there seems to be a legitimate use case, which is that some object might or might not have a code, but if it has a code, it must be have an entry present in th...