What is Boilerplate code? Concept summary and examples

What is Boilerplate?

• Boilerplate refers to the metal plate used by newspaper companies.
• Newspapers print the same content repeatedly using templates already made on metal plates.

Boilerplate code concept

• Boilerplate code refers to code that must be written repeatedly every time you start a new project. Boilerplate code is code that is repeated in a similar fashion in several places.
• This includes, for example, creating the structure of the project, initializing settings, loading libraries, etc. Alternatively, it refers to code that must be written repeatedly when implementing a specific function, such as a Getter & Setter Method.

Boilerplate code example

• Boilerplate code can occur in various languages.
• An example of code used as a boilerplate in Java is as follows:
  • Getter & Setter Method
  • equals() and hashCode() Method
  • toString() Method
  • Constructor Method
• The above codes are codes that must be written repeatedly every time a new class is created.

// 1. Getter & Setter Method
public class Person {
    private String name;
    private int age;

    // Getter Method
    public String getName() {
        return name;
    }

    // Setter Method
    public void setName(String name) {
        this.name = name;
    }

    // Getter Method
    public int getAge() {
        return age;
    }

    // Setter Method
    public void setAge(int age) {
        this.age = age;
    }
}

// 2. equals() and hashCode() Method
public class Person {
    private String name;
    private int age;

    // equals() Method
    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Person person = (Person) o;
        return age == person.age && Objects.equals(name, person.name);
    }

    // hashCode() Method
    @Override
    public int hashCode() {
        return Objects.hash(name, age);
    }
}

// 3. toString() Method
public class Person {
    private String name;
    private int age;

    // toString() Method
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

// 4. Constructor Method
public class Person {
    private String name;
    private int age;

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

How to reduce boilerplate code

• Boilerplate code is code that must be written repeatedly, so as the amount of code increases, the readability of the code may decrease.
• In Java, you can use the following methods to reduce boilerplate code.
  • Use IDE (Integrated Development Environment): Boilerplate code can be automatically generated using functions provided by the IDE.
  • Use the Lombok library: You can use the Lombok library to automatically generate Getter & Setter Method, equals() and hashCode() Method, toString() Method, Constructor Method, etc.
  • Use Annotation Processor: Boilerplate code can be automatically generated using the Annotation Processor.
  • Use Template Engine: Boilerplate code can be automatically generated using Template Engine.
• In Java, you can use the Lombok library to reduce the Boilerplate code as shown below.
  • Using @Data Annotation, you can automatically create Getter & Setter Method, equals() and hashCode() Method, toString() Method, and Constructor Method.
  • You can reduce code writing just by using @Data Annotation as shown below.

import lombok.Data;

@Data
public class Person {
    private String name;
    private int age;
}

• Depending on the language or framework, methods to reduce boilerplate code may vary. Find ways to reduce boilerplate code by using features provided by the language or framework you're using.