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| <title>Chapter 5. Covariance</title><link rel="stylesheet" href="aspectj-docs.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.44"><link rel="home" href="index.html" title="The AspectJTM 5 Development Kit Developer's Notebook"><link rel="up" href="index.html" title="The AspectJTM 5 Development Kit Developer's Notebook"><link rel="previous" href="autoboxing-and-method-dispatch.html" title="Inter-type method declarations and method dispatch"><link rel="next" href="covariance-and-join-point-matching.html" title="Covariant methods and Join Point matching"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Chapter 5. Covariance</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="autoboxing-and-method-dispatch.html">Prev</a> </td><th width="60%" align="center"> </th><td width="20%" align="right"> <a accesskey="n" href="covariance-and-join-point-matching.html">Next</a></td></tr></table><hr></div><div class="chapter"><div class="titlepage"><div><h2 class="title"><a name="covariance"></a>Chapter 5. Covariance</h2></div></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><a href="covariance.html#covariance-inJava5">Covariance in Java 5</a></dt><dt><a href="covariance-and-join-point-matching.html">Covariant methods and Join Point matching</a></dt></dl></div><div class="sect1"><a name="covariance-inJava5"></a><div class="titlepage"><div><h2 class="title" style="clear: both"><a name="covariance-inJava5"></a>Covariance in Java 5</h2></div></div><p> | |
| Java 5 (and hence AspectJ 5) allows you to narrow the return type | |
| in an overriding method. For example: | |
| </p><pre class="programlisting"> | |
| class A { | |
| public A whoAreYou() {...} | |
| } | |
| class B extends A { | |
| // override A.whoAreYou *and* narrow the return type. | |
| public B whoAreYou() {...} | |
| } | |
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