How to use lombok's @Tolerate on a constructor

Question

The @Tolerate annotation is an experimental feature in lombok where the target type is either a Method or a Constructor. The lombok website mentions as:

Any method or constructor can be annotated with @Tolerate and lombok will act as if it does not exist.

It states an example for a setter method:

@Setter
private Date date;

@Tolerate
public void setDate(String date) {
    this.date = Date.valueOf(date);
}

In the above example if we had NOT added @Tolerate, then lombok would NOT generate setDate(Date date) because a method of the same name already exists (even though parameter type is different). So, how it works for a method is clear from this example.

But I am not able to understand how this annotation is to be used for a constructor.

@AllArgsConstructor
public class One {
    private int id;
    private String name;

    // adding @Tolerate here does nothing. 
    public One(int a, int b) {
    }
}

In the above code, lombok would generate an all argument constructor even if another constructor with the same number of parameters but different type exist.

So, how can we use @Tolerate in the context of a constructor?

user_7821823 · Answer

The @Data, @Value and @Builder annotations create constructors (a constructor for all required arguments in the @Data case, and a constructor for all arguments in the @Value and @Buildercase). However, they do these only, if no other constructors exist. If you create your own constructor(s), @Data, @Value and @Builder will not create their constructors, unless you annotate your own constructor(s) with @Tolerate.

In a nutshell, @Tolerate on a constructor only makes a difference, if you use it together with @Data, @Value or @Builder. It has no effect, if you use it with @NoArgConstructor, @AllArgsConstructor or @RequiredArgsConstructor, just like Gautham noticed.

Example:

@Value
public class Main {
    private int id;
    private String name;
    
    @Tolerate // Now the allArgsConstructor will be created. If you omit the annotation, no allArgsConstructor will be created.
    public Main(String name) {
        this.name = name;
        this.id = 0;
    }
}

How to use lombok's @Tolerate on a constructor

1 Answers