How to create an object of record in Java?

How to create an object of record in Java?

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In Java, creating an object of record means defining a class that automatically generates getter and setter methods for its fields. This is achieved by using the record keyword, which was introduced in Java 14. Here's how you can do it:

public record Person(String name, int age) {
public static void main(String[] args) {
Person person = new Person("John", 30);
System.out.println(person.name()); // prints "John"
}
}

In this example, we define a class called Person that takes two parameters: name and age. The record keyword is used to indicate that this is a record.

public final record Person(String name, int age) {
public static void main(String[] args) {
Person person = new Person("John", 30);
System.out.println(person.name()); // prints "John"
person = person.withName("Jane");
System.out.println(person.name()); // prints "Jane"
}
}

In this example, we use the final keyword to make the record immutable. This means that once a record is created, its state cannot be changed.

In conclusion, creating an object of record in Java is a simple process that involves defining a class with the record keyword. Records provide several benefits, including better encapsulation and simplified code. However, they also have some limitations, such as limited inheritance support and inability to define private or protected fields.

When was record introduced in Java?

I'm happy to respond in English!

The introduction of records in Java is an exciting topic! Records are a new type of data class that was introduced in Java 14, which is part of the JDK 14 release in March 2020.

Before records were introduced, developers often used classes with a single constructor and no methods to create simple data structures. This approach had some limitations, such as requiring manual implementation of equals(), hashCode(), and toString() methods, which could be tedious and error-prone.

Records are designed to simplify the process of creating immutable data carriers by providing a concise syntax for defining such classes. With records, you can focus on the data itself rather than the boilerplate code that surrounds it.

Here's an example of how you might define a record in Java:

public record Person(String name, int age) {
public Person {
// constructor implementation
}
}

In this example, Person is a record with two properties: name and age. The constructor is automatically generated by the compiler, which simplifies the process of creating instances of the record.

One of the key benefits of records is that they allow for more concise code. For instance, you can use the following syntax to create an instance of the Person record:

Person person = new Person("John", 30);

This is much simpler than what you might have seen in earlier Java versions, where you would need to write a constructor and manually set each property.

Records also support pattern matching, which enables more expressive code. For example:

if (person.name().equals("John")) {
// do something
}

This syntax is reminiscent of pattern matching in functional languages like Haskell or Scala.

In addition to these benefits, records are also designed to work seamlessly with Java's existing ecosystem. You can use them as keys in maps, as values in lists, and even as function return types.

Overall, the introduction of records in Java 14 represents an exciting step forward for the language. It enables developers to write more concise, expressive code that is easier to maintain and understand.

In conclusion, records were introduced in Java 14 as part of the JDK 14 release in March 2020. They simplify the process of creating immutable data structures by providing a concise syntax for defining classes and support pattern matching for more expressive code.