Annotations from javax.validation.constraints not working

Question

What configuration is needed to use annotations from javax.validation.constraints like @Size, @NotNull, etc.? Here\'s my code:

Answer 1

I come here some years after, and I could fix it thanks to atrain's comment above. In my case, I was missing @Valid in the API that receives the Object (a POJO in my case) that was annotated with @Size. It solved the issue.

I did not need to add any extra annotation, such as @Valid or @NotBlank to the variable annotated with @Size, just that constraint in the variable and what I mentioned in the API...

Pojo Class:

...
@Size(min = MIN_LENGTH, max = MAX_LENGTH);
private String exampleVar;
...

API Class:

...
public void exampleApiCall(@RequestBody @Valid PojoObject pojoObject){
  ...
}

Thanks and cheers

Answer 2

You should use Validator to check whether you class is valid.

Person person = ....;
ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
validator = factory.getValidator();
Set<ConstraintViolation<Person>> violations = validator.validate(person);

Then, iterating violations set, you can find violations.

Answer 3

for method parameters you can use Objects.requireNonNull() like this: test(String str) { Objects.requireNonNull(str); } But this is only checked at runtime and throws an NPE if null. It is like a preconditions check. But that might be what you are looking for.

Answer 4

I came across this problem recently in a very similar situation: Met all requirements as the top-rated answer listed but still got the wrong result.

So I looked at my dependencies and found I was missing some of them. I corrected it by adding the missing dependencies.

I was using hibernate, the required dependencies were:

*Snapshot taken in class "Spring & Hibernate for Beginners" @ Udemy

Answer 5

In my case i removed these lines

1-import javax.validation.constraints.NotNull;

2-import javax.validation.constraints.Size;

3- @NotNull

4- @Size(max = 3)

Answer 6

You can also simply use @NonNull with the lombok library instead, at least for the @NotNull scenario. More details: https://projectlombok.org/api/lombok/NonNull.html