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<pre>public interface <span class="typeNameLabel">Extension</span></pre>
<div class="block"><p>
 Service interface implemented by extensions. An extension is a service provider declared in <code>META-INF/services</code>.
 </p>
 
 <p>
 Service providers may have <a href="../../event/Observes.html" title="annotation in jakarta.enterprise.event">observer methods</a>, which may observe any event,
 including any <a href="package-summary.html">container lifecycle event</a>, and obtain an injected
 <a href="Bean