@NonNull annotation in project Lombok

Question

I recently started to use lombok in my project. In lombok documentation, it is specified that @NonNull annotation can be configured to throw either NullPointerException or IllegalArgumentException. It is specified that by default NullPointerException will be thrown. It is also specified that to throw IllegalArgumentException, I should set lombok.nonNull.exceptionType = IllegalArgumentException. But, I am not understanding where I should specify lombok.nonNull.exceptionType = IllegalArgumentException in my code. `

import com.sandesha.lombak.domain.Employee;

import lombok.NonNull;

public class EmployeeOperation {

/**
 * @NonNull performs null check
 * @param e1
 * @param e2
 * @return
 */

public boolean isEqual(@NonNull Employee e1, @NonNull Employee e2)
{
    return e1.equals(e2);
}
}

Please help me. Thank you.

Answer 1

You need to create a file named lombok.config in the home directory of your project, which is the default lombok configuration file to your project. The file looks like:

lombok.nonNull.exceptionType = IllegalArgumentException
lombok.nonNull.flagUsage = [warning | error] 

You may see the project

Answer 2

This is not parameterized in the @NonNull annotation, it can be only specified in the Lombok configuration keys of @NonNull:

Supported configuration keys:

lombok.nonNull.exceptionType = [NullPointerException | IllegalArgumentException | Assertion] (default: NullPointerException).

[...]

Create a lombok.config file in your project root directory, containing this line:

lombok.nonNull.exceptionType = IllegalArgumentException

More details about the Lombok configuration system are in the Lombok documentation page.