Java Validation not working with @Value.Immutables

Question

I have been at it for 2 days but I can't figure out what I am missing.

My Immutables class looks like:

import org.immutables.value.Value;
import javax.validation.Valid;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotEmpty;

@Value.Immutable
public abstract class _MyClass {

    @Valid
    @NotBlank
    public abstract String field();

    @Valid
    @NotEmpty
    public abstract Set<@Valid @NotBlank String> terms();
}

The libraries in my build file:

Javax Validation Api
Hibernate Validator

Problems:

1. My generated class file for MyClass does not contain the javax validation
2. The following test code fails:

public void testMyClassValidation() {
        MyClass myClass = MyClass.builder().field("field").addAllTerms(Set.of()).build();

        Set<ConstraintViolation<RankingHint>> constraintViolations = Validation.buildDefaultValidatorFactory().getValidator().validate(myClass);
        assertEquals(1, constraintViolations.size()); // THIS IS ZERO
        //assertEquals("may not be null", constraintViolations.iterator().next().getMessage());
}

What am I doing wrong? I found a discussion thread where Immutables are supposed to work with Javax validation: https://github.com/immutables/immutables/issues/26