How to use Optional in Java

A Optional Object in Java is a container object that can contain empty and non-null values. If an Optional object contains a value, we say that it is present; if it does not contain a value, we say it is empty. Here, we will 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 and some best practices.

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What is 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 may contain a non-null value (in which case it is considered present) or may not contain any value (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 can be accessed by invoking the get() method.
• Absent: The Optional object represents the absence of a value; you cannot access its content with the get() method.

Why do developers need options in Java?

Optional is generally used as a return type for methods that do not always have a result to return. For example, a method that searches for a user by ID It may not find a match, in which case it will return an empty Optional object.

Optional can also help reduce the number of null pointer exceptions in your code. It is not intended to replace existing reference types, such as Chain either Listbut rather as an addition to the Java type system.

How to create an optional object in Java

There are several ways to create an optional object in Java, including static factory methods. empty() and of()that belong to the Optional class. You can create an optional object using the of() method, which will return an optional object containing the given value if the value is not null, or an empty optional object if the value is null.

Programmers can also use the deNullable() method, which will return an empty Optional object if the value is null, or an Optional object containing the given value if it is not null. Finally, you can create an empty Optional object using the empty() method.

Once you have created an Optional object, you can use the ispresent() method to check if it contains a non-null value. If so, you can use the get() method to retrieve the value. Developers can also use the getOrElse() method, which will return the value if present, or a default value if not.

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The Java isPresent and ifPresent methods

Developers can take advantage of the is present Method to check if an optional object is empty or not. He yes present Meanwhile, the method can check if a particular Optional object is not empty. The following code example illustrates how you can work with the yes present and is present methods in Java:

import java.util.Optional;
   public class OptionalDemo {  
      public static void main(String() args) {
         Optional obj1 = Optional.of
         ("This is a sample text"); 
         Optional obj2 = Optional.empty();
         if (obj1.isPresent()) {          
            System.out.println
            ("isPresent method called on obj1 returned true");
         }       
    obj1.ifPresent(s -> System.out.println
   ("ifPresent method called on obj1"));
    obj2.ifPresent(s -> System.out.println
    ("ifPresent method called on obj2 "));
   }
}

In the code example above, we first check if two optional objects exist, using the ispresent() method. We assign a value obj1so it will print the string “This is a sample text”. obj2however, it was assigned an empty value, so it won’t print anything. We then print more text to alert us that yes present was called on our two optional objects.

How to use optional objects in Java

There are several ways to create optional objects. The most common way is to use the static factory method. Optional(T)which creates an Optional object that is present and contains the given non-null value, as shown in the following code snippet:

Optional optional = Optional.of("value");

Additionally, we can create an empty Optional object using the static factory method. optional.emptyas shown in the following code example:

Optional optional = Optional.empty();

If we have a value that could be null, we can use the static factory method. Optional.ofNulable(T) to create an Optional object that may or may not be present:

Optional optional = Optional.ofNullable(null);

Programmers can also use methods like if present() and orelse() if you need to perform some action based on whether the optional has been set (whether it contains a certain value) or not respectively:

Optional optionalString = Optional.of("value");
optionalString.ifPresent(s -> System.out.println(s));

Pros and cons of using optional objects in Java

There are some key benefits of using Optional that Java developers should be aware of, including:

• Optional can help prevent Null pointer exception errors in making explicit when a variable can or cannot contain a value. This can result in cleaner, more readable code.
• Optional provides several methods that can be used to safely work with data that may or may not be present.
• Optional can be used as an ordinary class, meaning there is no need for special syntax to invoke methods or access fields.

Despite these benefits, there are also some potential disadvantages to using Optional:

• Optional can add significant overhead to the code runtime, since the Optional wrapper must be created and checked each time a variable is accessed.
• Some developers find Optional confusing and difficult to work with, which can lead to more bugs instead of fewer and, as a result, more development time and effort than usual.

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Alternatives to using optional objects in Java

There are some alternatives to using Optional, such as using the void check operator (?.)using a but statement, or using a ternary operator.

The null check operator can be used to check whether a value is null before accessing it. This can be done using the ?. operator before the variable name. For example, the following Java code will check if the variable alphabet is null before accessing it:

if (abc != null) {
//Write your code here
}

If the variable alphabet is not null, the code inside the Yeah the statement will be executed. He but The statement in the code above checks if the value is null before accessing it.

Best practices for using optionals

Below are some best practices to consider when using Optional in your Java code:

• Use Optional to reduce the number of null pointer exceptions and account for occasions when return values ​​are empty or missing.
• Do not use Optional as a dead stop for every type of null pointer. Coders still need to take into account method and constructor parameters that may also contain empty values.
• Consider the context of your Optional objects; Optional missing values ​​can mean different things, such as a particular value not being found or no value being found. Consider these possibilities.
• Use Optional as the return type and then retrieve its value if it is present or provide a different result if not.
• Do not use an optional parameter for methods or constructors. Using it that way results in sloppy code that is difficult to read and maintain.

Final Thoughts on Using Optional Objects in Java

Optional is a new feature in Java 8 that provides a way to handle null values ​​in a more elegant way. He java.util.Optional The class was introduced in Java 8 as a way to address the common problem of null pointer exceptions. By using Optional, programmers can avoid Null pointer exceptions and write cleaner code.

Do you want to learn more about objects and classes in Java? We recommend reading our tutorial. What is an abstract class? in Java as the next step.