void () { this.update( () -> myChildren.clear(), (builder, packagingElementEntity) -> { CompositePackagingElementEntity entity = (CompositePackagingElementEntity)packagingElementEntity; // I just don't understand what to do to avoid this warning //noinspection unchecked builder.modifyEntity(CompositePackagingElementEntity.Builder.class, entity, o -> { //noinspection unchecked o.setChildren(new ArrayList<>()); return Unit.INSTANCE; }); } ); }