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e21cbe82a9
Where possible update Java documentation links to Java 11. Additionally update some other links to use HTTPS.
47 lines
1.5 KiB
XML
47 lines
1.5 KiB
XML
<!DOCTYPE qhelp PUBLIC
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"-//Semmle//qhelp//EN"
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"qhelp.dtd">
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<qhelp>
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<overview>
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<p>To be able to use the <code>isAnnotationPresent</code> method on an <code>AnnotatedElement</code> at runtime,
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an annotation must be explicitly annotated with a <code>RUNTIME</code> retention policy.
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Otherwise, the annotation is not retained at runtime and cannot be observed using reflection.
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</p>
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</overview>
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<recommendation>
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<p>Explicitly annotate annotations with a <code>RUNTIME</code> retention policy
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if you want to observe their presence using <code>AnnotatedElement.isAnnotationPresent</code>
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at runtime.
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</p>
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</recommendation>
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<example>
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<p>In the following example, the call to <code>isAnnotationPresent</code> returns <code>false</code>
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because the annotation cannot be observed using reflection.</p>
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<sample src="AnnotationPresentCheck.java" />
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<p>To correct this, the annotation is annotated with a <code>RUNTIME</code> retention policy.</p>
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<sample src="AnnotationPresentCheckFix.java" />
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</example>
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<references>
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<li>
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Java API Specification:
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<a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/annotation/Retention.html">Annotation Type Retention</a>,
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<a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/annotation/RetentionPolicy.html#RUNTIME">RetentionPolicy.RUNTIME</a>,
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<a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/reflect/AnnotatedElement.html#isAnnotationPresent(java.lang.Class)">AnnotatedElement.isAnnotationPresent()</a>.
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</li>
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</references>
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</qhelp>
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