Summary
This rule flags Apex code that relies on JDK based locale logic (like Locale.getDefault() or DateFormat) instead of using locale neutral, Salesforce safe methods. To ensure your app behaves reliably across regions and remains compatible with Salesforce's evolving platform, always use standard Apex methods and apply locale formatting only at the final output stage.
Why It Matters
Salesforce is transitioning from Oracle’s JDK locale formats to ICU (International Components for Unicode). This shift affects how data types like dates, times, numbers, currency, and addresses are formatted based on user locale.
Additionally:
Users can change their locale at any time.
Locale definitions are regularly updated to meet new international standards.
JDK-based code is not guaranteed to behave consistently across Salesforce environments.
To avoid runtime errors and formatting inconsistencies, it’s essential to follow locale neutral coding practices.