Javax @NotNull annotation usage

Question

I have a simple method to get a list of documents for a given companyId. Here is the method:

@Override
public List<Documents> getDocumentList(@NotNull Integer companyId) {
    Company company = new Company(companyId);
    return this.documentRepository.findByCompany(company);
}

I wanted to use Javax validation constraints to ensure that the companyId being passed in, is not null. But it seems to not have any effect, as I'm able to pass in a null value, and it flows down to the findByCompany call on the repository. I also added @Valid before @NotNull to force validation, but that too didn't do anything.

I could always write a couple of lines to check for a null value, but wanted to use javax.validation annotations to make the code more readable and concise. Is there a way to make the annotations work on method params?

sisanared · Accepted Answer · 2018-05-19T03:07:49.697

11

To activate parameter validation, simply annotate the class with @Validated

import org.springframework.validation.annotation.Validated;

edited May 19 '18 at 03:07

answered May 02 '17 at 14:47

sisanared

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What if I ain't using spring – Anurag Awasthi Jun 08 '18 at 07:03
You could use @NonNull from projectlombok (lombok.NonNull) – sisanared Aug 16 '18 at 09:08
Adding more annotations will have any impact on performance? As adding one more layer before actual method gets invoked? – Ravik Apr 04 '19 at 05:25
@Validated's impact is negligible to none – sisanared Apr 10 '19 at 08:51

Moshe Arad · Answer 2 · 2017-04-28T02:26:49.290

2

From The Java EE 6 Tutorial:

The Bean Validation model is supported by constraints in the form of annotations placed on a field, method, or class of a JavaBeans component, such as a managed bean.

You should place your validation of a field related to a declared bean, something like this:

@Entity
@Table(name="users")
public class BackgammonUser {

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Long userId;

    @Column(name="username")
    @NotBlank
    private String userName;

    @NotBlank
    private String password;

    @NotNull
    private Boolean enabled;
}

The BackgammonUser is considered to be a bean.

edited Apr 28 '17 at 02:26

answered Apr 28 '17 at 02:25

Moshe Arad

3,587
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I am aware of this. I did not want to create a bean for a single param – sisanared Apr 28 '17 at 02:26
Then it's a limitation. you can look it up as well in The Java EE 6 Tutorial – Moshe Arad Apr 28 '17 at 02:27
1

Thank you. I guess, I have to write the null check manually after all :) – sisanared Apr 28 '17 at 02:31
Can we use the @NotNull annotation on the Entity class, instead of checking for each variable ?? – Rishi Aug 04 '20 at 14:57

score 0 · Answer 3 · edited Apr 25 '18 at 09:53

If you @Inject a class with your method, its working as expected.

@Stateless
public class MyBean{ 
    @Inject
    TestClass test;
}

and

public class TestClass {
    public List<Documents> getDocumentList(@NotNull Integer companyId)
    {
        //...
    }
}

ConstraintViolationException when you call your method with null parameter:

WFLYEJB0034: EJB Invocation failed on component MyBean for method ...:
javax.ejb.EJBException: javax.validation.ConstraintViolationException:
1 constraint violation(s) occurred during method validation.

score -6 · Answer 4 · answered Apr 28 '17 at 06:41

-6

@NotNull Annotation,

A method should not return null.
A variable (like fields, local variables, and parameters) cannot hold null value.

answered Apr 28 '17 at 06:41

Balasubramanian

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Downvote as providing some general programming hints inapropriate to the question does not help anyone. And furthermore your second statement is confusing / incomplete (or wrong if meant as written). – Sebastian Jul 26 '18 at 08:35

Javax @NotNull annotation usage

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