Java has a bad side that everybody hates 😓, what is it?

A lot of boilerplate code is the same for most of the applications we write.

Like what? 🧐

• Getters
• Setters
• Constructors
• Builder pattern
• and many more...

Wouldn't it be nice if someone took care of that work for us?
That is where Lombok introduces itself.

What does it do? 👀

It generates the byte code for those common tasks (Getters, Setters, etc..) and puts them in our .class files which make them usable by the code we write.

How? 🔧

We need to add the Lombok dependency to our Maven build.
Then, we just need to annotate the wanted classes, fields with some Lombok annotations.

Let's look at some code! 👩🏻‍💻

No Lombok 🧟

public class Human {  
    private int id;  
    private String name;  
    private int ageInYears;  

    public Human() { }  

    public Human(int id, String name, int ageInYears) {  
        this.id = id;  
        this.name = name;  
        this.ageInYears = ageInYears;  
    }  

    public int getId() {  
        return id;  
    }  

    public String getName() {  
        return name;  
    }  

    public int getAgeInYears() {  
        return ageInYears;  
    }  

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

    public void setAgeInYears(int ageInYears) {  
        this.ageInYears = ageInYears;  
    }  

    // Builder pattern  
  public Human id(int id){  
        this.id = id;  
        return this;  
    }  
    public Human name(String name){  
        this.name = name;  
        return this;  
    }  
    public Human ageInYears(int ageInYears){  
        this.ageInYears = ageInYears;  
        return this;  
    }  

    @Override  
  public String toString(){  
        return String.format("Human(id=%s, name=%s, ageInYears=%s)",  
                this.id, this.name, this.ageInYears);  
    }  
}

Lombok 🤴

import lombok.*;  
@Getter @Setter  
@AllArgsConstructor @NoArgsConstructor  
@Builder @ToString  
public class Human {  
    @Setter(AccessLevel.NONE)  
    private int id;  
    private String name;  
    private int ageInYears;  
}

The Maven dependency looks like this

<dependency>  
    <groupId>org.projectlombok</groupId>  
    <artifactId>lombok</artifactId>  
    <version>1.18.16</version>  
    <scope>provided</scope>  
</dependency>

Note: the version part will change depending on the last release of Lombok.

What just happened? 🕵️‍♀️ 🕵️

• we used annotations to generate
  • Getters
  • Setters
  • Constructors
  • Builder pattern
  • toString implementation

We can also make tweaks on some annotations, like the setter for the id field.

• We set its access level to None, meaning that we don't a setter to be generated for it.

Was it worth it? 📊📊

We wrote 52 lines when not using Lombok.
We wrote 8 lines when using Lombok.

Lombok helped us shrink our code size by nearly 4 times. Those numbers can go up even more when having more variables in our classes.

Lombok has a lot more annotations that offer a ton of help, to view them all visit their website.

Conclusion 👇🏾

Lombok helps us focus on our business code and not worry about the little details of getters/setters/constructors/common design patterns and other Java constructs.

Code 👨🏽‍💻

GitHub