When doing `String::toLowerCase()/toUpperCase()` conversions, use an explicit locale argument to specify the case transformation rules. Using `String::toLowerCase()` without arguments implicitly uses `Locale::getDefault()`. The problem is that the default locale depends on the current JVM setup (and usually on the system in which it is running). Using the system default may be exactly what you want (e.g. if you are manipulating strings you got through standard input), but it may as well not be the case (e.g. if you are getting the string over the network or a file, and the encoding is well-defined and independent of the environment). In the latter case, using the default locale makes the case transformation brittle, as it may yield unexpected results on a machine whose locale has other case translation rules. For example, in Turkish, the uppercase form of `i` is `İ` (U+0130, not ASCII) and not `I` (U+0049) as in English. The rule is intended to *force* developers to think about locales when dealing with strings. By taking a conscious decision about the choice of locale at the time of writing, you reduce the risk of surprising behaviour down the line, and communicate your intent to future readers. UseLocaleWithCaseConversions (Priority: 1, Ruleset: Error Prone) https://docs.pmd-code.org/snapshot/pmd_rules_java_errorprone.html#uselocalewithcaseconversions

Ensure that resources (like `java.sql.Connection`, `java.sql.Statement`, and `java.sql.ResultSet` objects and any subtype of `java.lang.AutoCloseable`) are always closed after use. Failing to do so might result in resource leaks. Note: It suffices to configure the super type, e.g. `java.lang.AutoCloseable`, so that this rule automatically triggers on any subtype (e.g. `java.io.FileInputStream`). Additionally specifying `java.sql.Connection` helps in detecting the types, if the type resolution / auxclasspath is not correctly setup. Note: Since PMD 6.16.0 the default value for the property `types` contains `java.lang.AutoCloseable` and detects now cases where the standard `java.io.*Stream` classes are involved. In order to restore the old behaviour, just remove "AutoCloseable" from the types. CloseResource (Priority: 1, Ruleset: Error Prone) https://docs.pmd-code.org/snapshot/pmd_rules_java_errorprone.html#closeresource