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Learning Kotlin: Data Classes

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Learning Kotlin: Data Classes

Want to avoid writing long lines of code in Java? Kotlin makes using data classes extremely easy.

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Wow! Data classes are awesome! I really like how classes are handled in Kotlin. However, data classes are the pinnacle of that work. The goal of this tutorial is to convert the following Java class to Kotlin:

package i_introduction._6_Data_Classes;

import util.JavaCode;

public class JavaCode6 extends JavaCode {

    public static class Person {
        private final String name;
        private final int age;

        public Person(String name, int age) {
            this.name = name;
            this.age = age;
        }

        public String getName() {
            return name;
        }

        public int getAge() {
            return age;
        }
    }
}


And, what does that look like in Kotlin?

data class Person(val name: String, val age: Int)


Yup, a single line. The data annotation adds a number of important functions (like ToString and copy). We then declare the class with a constructor that takes two parameters and both become properties.

Another important thing I learned with this information is that Kotlin has both a val and var keyword for variables. We have seen var already, and val is for read-only variables.

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Topics:
java ,kotlin ,classes ,data ,code ,tutorial

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