Planned lessonJNR-026-L04

Exception translation

Lesson 4 of 5
Junior

On This Lesson 4 topics

In this lesson
Planned topics
Draft outline details
Practice

This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.

In this lesson

understand why you get DataAccessException instead of SQLException.

Planned topics

SQLException is checked and database-specific (error codes, SQL states).
Spring catches it and rethrows an unchecked DataAccessException subclass, for example DuplicateKeyException, DataIntegrityViolationException, EmptyResultDataAccessException.
This keeps services independent of the database and of JDBC.
Catch a specific subclass at one place that can act (for example turn a duplicate into 409); do not catch DataAccessException everywhere.
Unhandled ones go to the global exception handler.

Draft outline details

Demonstration

java

try {
    jdbc.sql("insert into product(sku, name) values (:sku, :name)")
        .param("sku", sku).param("name", name).update();
} catch (DuplicateKeyException e) {
    throw new SkuAlreadyExistsException(sku);
}

Check your understanding

Is DataAccessException checked or unchecked?

Show answer

Unchecked.

Practice

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