Warning - cannot be null

cristobal.arevalo · July 11, 2025, 12:09am

Hello, I am having problems with the Entity Inspector. I have created an entity named ESCUELA with two fields: rbd and name. Both are required. When I go to entity inspector for escuela, these two fields are shown, as expected but when I press save I get an error. It’s in Spanish but it means “warning , cannot be null” .
Screenshot 2025-07-10 at 8.06.59 PM

Any ideas?

@JmixEntity
@Table(name = “ESCUELA”)
@Entity
public class Escuela {
@JmixGeneratedValue
@Column(name = “ID”, nullable = false)
@Id
private UUID id;

@Column(name = "VERSION", nullable = false)
@Version
private Integer version;

@CreatedBy
@Column(name = "CREATED_BY")
private String createdBy;

@CreatedDate
@Column(name = "CREATED_DATE")
private OffsetDateTime createdDate;

@LastModifiedBy
@Column(name = "LAST_MODIFIED_BY")
private String lastModifiedBy;

@LastModifiedDate
@Column(name = "LAST_MODIFIED_DATE")
private OffsetDateTime lastModifiedDate;

@DeletedBy
@Column(name = "DELETED_BY")
private String deletedBy;

@DeletedDate
@Column(name = "DELETED_DATE")
private OffsetDateTime deletedDate;

@Column(name = "RBD", nullable = false, length = 7)
@NotNull
private String rbd;

@InstanceName
@Column(name = "NOMBRE", nullable = false)
@NotNull
private String nombre;

public String getNombre() {
    return nombre;
}

public void setNombre(String nombre) {
    this.nombre = nombre;
}

public String getRbd() {
    return rbd;
}

public void setRbd(String rbd) {
    this.rbd = rbd;
}

public OffsetDateTime getDeletedDate() {
    return deletedDate;
}

public void setDeletedDate(OffsetDateTime deletedDate) {
    this.deletedDate = deletedDate;
}

public String getDeletedBy() {
    return deletedBy;
}

public void setDeletedBy(String deletedBy) {
    this.deletedBy = deletedBy;
}

public OffsetDateTime getLastModifiedDate() {
    return lastModifiedDate;
}

public void setLastModifiedDate(OffsetDateTime lastModifiedDate) {
    this.lastModifiedDate = lastModifiedDate;
}

public String getLastModifiedBy() {
    return lastModifiedBy;
}

public void setLastModifiedBy(String lastModifiedBy) {
    this.lastModifiedBy = lastModifiedBy;
}

public OffsetDateTime getCreatedDate() {
    return createdDate;
}

public void setCreatedDate(OffsetDateTime createdDate) {
    this.createdDate = createdDate;
}

public String getCreatedBy() {
    return createdBy;
}

public void setCreatedBy(String createdBy) {
    this.createdBy = createdBy;
}

public Integer getVersion() {
    return version;
}

public void setVersion(Integer version) {
    this.version = version;
}

public UUID getId() {
    return id;
}

public void setId(UUID id) {
    this.id = id;
}

update: So I re created the entity only with id, rbd and name and same error from Entity Inspector:

@JmixEntity
@Table(name = “ESCUELA”)
@Entity
public class Escuela {
@JmixGeneratedValue
@Column(name = “ID”, nullable = false)
@Id
private UUID id;

@Column(name = "RBD", nullable = false, length = 7)
@NotNull
private String rbd;

@InstanceName
@Column(name = "NOMBRE", nullable = false)
@NotNull
private String nombre;

public String getNombre() {
    return nombre;
}

public void setNombre(String nombre) {
    this.nombre = nombre;
}

public String getRbd() {
    return rbd;
}

public void setRbd(String rbd) {
    this.rbd = rbd;
}

public UUID getId() {
    return id;
}

public void setId(UUID id) {
    this.id = id;
}

}

EDIT 2: When I disable MANDATORY for both fields it works and no more errors. In both scenarios I made sure data was entered in both fields so I am still wondering why this happens.

d.kremnev · July 11, 2025, 6:18am

Hi!

Unfortunately, I can’t reproduce your problem.

There is the code for my TestEntity entity:

@JmixEntity
@Table(name = "TEST_ENTITY")
@Entity
public class TestEntity {
    @JmixGeneratedValue
    @Column(name = "ID", nullable = false)
    @Id
    private UUID id;

    @NotNull
    @InstanceName
    @Column(name = "NAME", nullable = false)
    private String name;

    @NotNull
    @Column(name = "TEST_PROPERTY", nullable = false, length = 7)
    private String testProperty;

    public String getTestProperty() {
        return testProperty;
    }

    public void setTestProperty(String testProperty) {
        this.testProperty = testProperty;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public UUID getId() {
        return id;
    }

    public void setId(UUID id) {
        this.id = id;
    }

}

I can save my entity without any warnings:
Screen Recording 2025-07-11 at 10.15.43

Could you please provide a small test project that reproduces the problem?

Best regards,
Dmitriy

cristobal.arevalo · March 30, 2026, 5:48pm

HI Dmitriy, I came back to this post because I am facing the same issue with Jmix 2.7.6.
I am attaching a test project that is having the problem.

When working with a project without tabbed mode, I am able to bypass the error by doing a MANUAL BUILD of the project before running it (dont know why this solution works?)
but this solution isnt working with a project with Tabbed mode.

Claude Code did some analysis and it says this:

“The issue is that the @NotNull Bean Validation annotations on the entity fields interfere with the Entity Inspector. When it creates a new entity instance (before you fill in the fields), it validates the whole entity and fails because the fields are momentarily null.” “Jmix’s Entity Inspector instantiates a new empty entity object before you fill in any fields. The @NotNull Bean Validation runs against that empty instance and throws the error immediately, even though you’re about to provide values.”

Then it went deeper:

"Found the root cause. It’s a confirmed incompatibility between jmix-tabbedmode and jmix-datatools.
Here’s the exact sequence in your Tabbed Mode app when clicking “Create” in Entity Inspector:
Step 1 — Tabbed Mode’s DetailViewBuilderProcessor.build() calls detailView.setEntityToEdit(entityA) (from the newEntitySupplier). This merges Entity A (null fields) into the view’s DataContext.
Step 2 — Views.open() then calls sendNavigationEvent() because the route parameters (entityName=Escuela, entityId=new) are present. This fires processBeforeEnterInternal on the view, which calls EntityInspectorDetailView.setupEntityToEdit(“new”) → createNewItemByMetaClass(), creating Entity B via dataContext.create(). Entity B ends up in the container and the form binds to it.
Step 3 — The user fills in the form (updating Entity B). Both Entity A (null fields) and Entity B (user values) are in the DataContext.
Step 4 — dataContext.save() persists both:
•
Entity A → INSERT with all-null fields → DB constraint fires (or, with @NotNull, EclipseLink runs Bean Validation first → ConstraintViolationException)
•
Entity B → INSERT with user values → would succeed, but the transaction already failed
The @NotNull annotations are irrelevant to the fix. The real problem is the double entity creation caused by jmix-tabbedmode triggering two separate setEntityToEdit calls on the EntityInspectorDetailView.
Summary: This is a bug in the integration of jmix-tabbedmode 2.7.6 with jmix-datatools — the Entity Inspector was not designed to work with Tabbed Mode’s navigation interception. "

I uploaded the test project to WeTransfer: Unique Download Link | WeTransfer

d.kremnev · March 31, 2026, 6:21am

Hi!

Thanks for the test project.

I couldn’t reproduce your problem even with the test project you provided. My failure may be due to the fact that I changed the database configuration to HSQLDB to run the project.

Offtop:

To avoid publishing a large archive on a third-party file-sharing service, you can use the zipProject gradle task. It compresses the project without unnecessary files. The archive can then be uploaded directly to a forum post.
I couldn’t run your project in its configuration because it has a Postgres database configured as its data source. I don’t have the same database schema as your environment. If you want to share the project along with the database, you need to use HSQLDB in file.

Best regards,
Dmitriy

cristobal.arevalo · March 31, 2026, 12:24pm

Hi Dmitriy, thanks for your response.

Here’s a new project, with the HSQLDB included. The problem persists.
test_project.zip (118.9 KB)
try creating a Escuela record through Entity Inspector. The popup appears “may not be null”

d.kremnev · April 1, 2026, 7:52am

Hi!

Thank you for test project! I was able to reproduce the issue.
I have created an issue to fix the bug in the Jmix 2.8.1 release: Entity Inspector can't save new entity with mandatory attributes for TabbedMode · Issue #5182 · jmix-framework/jmix · GitHub

If you need a fix urgently, you can override the EntityInspectorDetailView in your application and add the following code to the controller:

    @Override
    protected void setupEntityToEdit(Object entityToEdit) {
        container = initMainContainer(entityToEdit);
        isNew = entityStates.isNew(entityToEdit);
    }

Best regards,
Dmitriy

cristobal.arevalo · April 2, 2026, 4:23pm

Hi Dmitriy
Many thanks! I am glad a solution was found.

I was experiencing the same problem with projects up to version 2.7.6 without the tabs add-on , but I am unable to reproduce the issue now, maybe the latest update to jmix studio solved it? The difference was that I was able to bypass the error in projects without the add-on, by doing a Manual build of the project after creating the entity and before debugging. Not sure why this worked.
I haven’t tried to reproduce it in framework 2.8 yet.

Regards

Cristóbal Arévalo