MissingLocaleArgument.qhelp

<!DOCTYPE qhelp PUBLIC
  "-//Semmle//qhelp//EN"
  "qhelp.dtd">
<qhelp>


<overview>
<p>
The parameterless versions of <code>String.toUpperCase()</code> and <code>String.toLowerCase()</code> use the default locale of the Java Virtual Machine when
transforming strings. This can cause unexpected behavior for certain locales. 
</p>

</overview>
<recommendation>
<p>Use the corresponding methods with explicit locale parameters to ensure that the results are consistent 
across all locales. For example:</p>

<p><code>System.out.println("I".toLowerCase(java.util.Locale.ENGLISH));</code></p>

<p>prints <code>i</code>, regardless of the default locale.</p>

</recommendation>
<example>

<p>In the following example, the calls to the parameterless functions may return different strings 
for different locales. For example, if the default locale is ENGLISH, the function <code>toLowerCase()</code>
converts a capital <code>I</code> to <code>i</code>; if the default locale is TURKISH, the function 
<code>toLowerCase()</code> converts a capital <code>I</code> to the Unicode Character "Latin small 
letter dotless i" (U+0131).
</p>

<p>To ensure that an English string is returned, regardless of the default locale, the example shows 
how to call <code>toLowerCase</code> and pass <code>locale.ENGLISH</code> as the argument. (This 
assumes that the text is English. If the text is Turkish, you should pass 
<code>locale.TURKISH</code> as the argument.)</p>

<sample src="MissingLocaleArgument.java" />

</example>
<references>


<li>
Java API Specification:
<a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/String.html#toUpperCase()">String.toUpperCase()</a>.
</li>


</references>
</qhelp>