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<qhelp>

<overview>

<p>Type shadowing occurs if two types have the same name but one is defined within

the scope of the other. This can arise if you introduce a type variable

with the same name as an imported class.</p>

<p>Type shadowing may cause the two types to be confused, which can lead to various problems.</p>

</overview>

<recommendation>

<p>Name the type variable so that its name does not clash with the

imported class.</p>

</recommendation>

<example>

<p>In the following example, the type <code>java.util.Map.Entry</code> is imported at the top of the

file, but the class <code>Mapping</code> is defined with two type variables,

<code>Key</code> and <code>Entry</code>. Uses of <code>Entry</code> within the

<code>Mapping</code> class refer to the type variable, and not the imported

interface. The type variable therefore shadows <code>Map.Entry</code>.</p>

<sample src="TypeVariableHidesType.java" />

<p>To fix the code, the type variable <code>Entry</code> on line 4 should be renamed.</p>

</example>

<references>

<li>

Help - Eclipse Platform:

<a href="https://help.eclipse.org/2020-12/advanced/content.jsp?topic=/org.eclipse.jdt.doc.user/reference/preferences/java/compiler/ref-preferences-errors-warnings.htm">Java Compiler Errors/Warnings Preferences</a>.

</li>

<li>

Java Language Specification:

<a href="https://docs.oracle.com/javase/specs/jls/se11/html/jls-6.html#jls-6.4">6.4 Shadowing and Obscuring</a>.

</li>

</references>

</qhelp>