Hibernate ConstraintViolationException ☕ Java

org.hibernate.exception.ConstraintViolationException: could not execute statement

The database rejected an insert/update because of a constraint (unique, foreign key, not null).

Seen on: Java

Meaning

Hibernate wraps the JDBC error; the root cause at the bottom of the stack names the constraint (e.g. Duplicate entry, violates foreign key constraint).

Common causes

  • Duplicate unique value
  • Missing referenced row (FK)
  • NULL in a NOT NULL column
  • Bean Validation (jakarta.validation) annotations not checked before save

⚡ Quick fix

  1. Scroll to the root cause for the DB message
  2. Validate before saving
  3. Translate to a 409/422 response in your API

Detailed fix by platform

Java

  1. Spring: catch DataIntegrityViolationException at the service/controller boundary

How to diagnose

  1. Root cause — Which constraint?
  2. Data — Which value violates it?

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