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Implied default locale in case conversion

Implied default locale in case conversion

Calling String#toLowerCase() or #toUpperCase() without specifying an explicit locale is a common source of bugs. The reason for that is that those methods will use the current locale on the user's device, and even though the code appears to work correctly when you are developing the app, it will fail in some locales. For example, in the Turkish locale, the uppercase replacement for i is not I.

If you want the methods to just perform ASCII replacement, for example to convert an enum name, call String#toUpperCase(Locale.US) instead. If you really want to use the current locale, call String#toUpperCase(Locale.getDefault()) instead.

Issue id: DefaultLocale

Inspection Details

Available in:

IntelliJ IDEA 2023.3, Qodana for Android 2023.3, Qodana for JVM 2023.3


Android, 2022.3.1 Beta 2

Last modified: 13 July 2023