@FieldDefaults

New default field modifiers for the 21st century.

@FieldDefaults was introduced as experimental feature in lombok v0.11.4.

Experimental

Experimental because:

Would be nice if you could stick this on the package-info.java package to set the default for all classes in that package.
[UPDATE 2022-02-04] Currently simply having a lombok.config entry of lombok.fieldDefaults.defaultPrivate = true (or, analogously, defaultFinal) is enough to modify every source file that is affected by that configuration, even if said source file has absolutely no trace whatsoever of lombok anything inside it. We're not quite sure if this is a good idea. Our current point of view is that this is too much magic, and there is an alternative plan: meta-annotations. Until at least the meta-annotations idea has been explored and discarded, this feature will not be leaving experimental in its current state. Most likely, if it ever does, the lombok.FieldDefaults annotation will be required, though, you may set it via the to be built meta-annotation.

Current status: neutral - Currently we feel this feature may not move out of experimental status without changes.

Overview

The @FieldDefaults annotation can add an access modifier (public, private, or protected) to each field in the annotated class or enum. It can also add final to each field in the annotated class or enum.

To add final to each (instance) field, use @FieldDefaults(makeFinal=true). Any non-final field which must remain nonfinal can be annotated with @NonFinal (also in the lombok.experimental package).

To add an access modifier to each (instance) field, use @FieldDefaults(level=AccessLevel.PRIVATE). Any field that does not already have an access modifier (i.e. any field that looks like package private access) is changed to have the appropriate access modifier. Any package private field which must remain package private can be annotated with @PackagePrivate (also in the lombok.experimental package).

With Lombok


import lombok.AccessLevel;

import lombok.experimental.FieldDefaults;

import lombok.experimental.NonFinal;

import lombok.experimental.PackagePrivate;



@FieldDefaults(makeFinal=true, level=AccessLevel.PRIVATE)

public class FieldDefaultsExample {

  public final int a;

  int b;

  @NonFinal int c;

  @PackagePrivate int d;

  

  FieldDefaultsExample() {

    a = 0;

    b = 0;

    d = 0;

  }

}

Vanilla Java


public class FieldDefaultsExample {

  public final int a;

  private final int b;

  private int c;

  final int d;

  

  FieldDefaultsExample() {

    a = 0;

    b = 0;

    d = 0;

  }

}

Supported configuration keys:

lombok.fieldDefaults.flagUsage = [warning | error] (default: not set): Lombok will flag any usage of @FieldDefaults as a warning or error if configured.
lombok.fieldDefaults.defaultPrivate = [true | false] (default: false): (Since 1.16.8) If set to true, every field in every class or enum anywhere in the sources being compiled will be marked as private unless it has an explicit access modifier or the @PackagePrivate annotation, or an explicit @FieldDefaults annotation is present to override this config key.
lombok.fieldDefaults.defaultFinal = [true | false] (default: false): (Since 1.16.8) If set to true, every field in every class or enum anywhere in the sources being compiled will be marked as final unless it has the @NonFinal annotation, or an explicit @FieldDefaults annotation is present to override this config key.

Small print

Like other lombok handlers that touch fields, any field whose name starts with a dollar ($) symbol is skipped entirely. Such a field will not be modified at all.