How to Resolve FlywayException: Unable to Scan for SQL Migrations in classpath:db/migration?

What steps can I take to troubleshoot the FlywayException indicating it cannot scan for SQL migrations in the specified classpath location?

// Example of a Flyway migration script: 
-- V1__Create_person_table.sql
CREATE TABLE person (
    id INT PRIMARY KEY,
    name VARCHAR(100) NOT NULL
); // Make sure your migration files are named correctly.

Flyway is a widely-used database migration tool that supports versioned migrations for SQL databases. The error 'FlywayException: Unable to scan for SQL migrations in location: classpath:db/migration' typically occurs when Flyway is unable to locate the migration files at the specified path. This can happen due to various reasons including incorrect path configuration, missing files, or issues with the classpath setup.

// Example Flyway configuration in Java:
Flyway flyway = Flyway.configure()
                .dataSource(url, user, password)
                .locations("classpath:db/migration") // Ensure this is correct
                .load();
flyway.migrate();

Causes

• Incorrect path specified in Flyway configuration.
• Migration scripts are not in the expected directory.
• Files are named incorrectly (i.e., missing 'V' prefix or version number).
• Classpath issues where the resource is not being loaded correctly.

Solutions

• Verify that the migration scripts are indeed located in the directory specified by the path in your Flyway configuration.
• Ensure that the naming convention for your migration files follows the format 'V{version}__{description}.sql', e.g., 'V1__Create_person_table.sql'.
• Check your application's classpath settings to ensure that the directory containing migration files is included in the classpath.
• If using a packaged application (like a JAR), ensure that the migration files are correctly packaged within the JAR under `db/migration`.

Mistake: Skipping the naming conventions for migration files.

Solution: Always follow 'V{version}__{description}.sql' format for the files.

Mistake: Providing an incorrect relative path to the migration folder in the Flyway configuration.

Solution: Double-check the path set in the Flyway configuration corresponds to the actual location of the files in your project.

Mistake: Not including the migration files in the JAR during a packaged build.

Solution: Ensure your build tool (e.g., Maven, Gradle) is configured to include these resources.