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    <p>Actually, you <em>can</em> do what you want. If you want to provide multiple interfaces or a class plus interfaces, you have to have your wildcard look something like this:</p> <pre><code>&lt;T extends ClassA &amp; InterfaceB&gt; </code></pre> <p>See the <a href="http://java.sun.com/docs/books/tutorial/java/generics/index.html" rel="noreferrer">Generics Tutorial</a> at sun.com, specifically the <a href="http://java.sun.com/docs/books/tutorial/java/generics/bounded.html" rel="noreferrer">Bounded Type Parameters</a> section, at the bottom of the page. You can actually list more than one interface if you wish, using <code>&amp; InterfaceName</code> for each one that you need.</p> <p>This can get arbitrarily complicated. To demonstrate, see the JavaDoc declaration of <a href="http://java.sun.com/javase/6/docs/api/java/util/Collections.html#max(java.util.Collection)" rel="noreferrer"><code>Collections#max</code></a>, which (wrapped onto two lines) is:</p> <pre><code>public static &lt;T extends Object &amp; Comparable&lt;? super T&gt;&gt; T max(Collection&lt;? extends T&gt; coll) </code></pre> <p>why so complicated? As said in the Java Generics FAQ: <a href="http://www.angelikalanger.com/GenericsFAQ/FAQSections/ProgrammingIdioms.html#FAQ104" rel="noreferrer">To preserve binary compatibility</a>.</p> <p>It looks like this doesn't work for variable declaration, but it does work when putting a generic boundary on a class. Thus, to do what you want, you may have to jump through a few hoops. But you can do it. You can do something like this, putting a generic boundary on your class and then:</p> <pre><code>class classB { } interface interfaceC { } public class MyClass&lt;T extends classB &amp; interfaceC&gt; { Class&lt;T&gt; variable; } </code></pre> <p>to get <code>variable</code> that has the restriction that you want. For more information and examples, check out page 3 of <a href="http://www.javabeat.net/articles/33-generics-in-java-50-4.html" rel="noreferrer">Generics in Java 5.0</a>. Note, in <code>&lt;T extends B &amp; C&gt;</code>, the class name must come first, and interfaces follow. And of course you can only list a single class.</p>
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    1. POJava Generics Wildcarding With Multiple Classes
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    1. COBut why do I have to cast the object to T when returning it?
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    2. CO@BernhardV: You need to provide more information before I can answer it. In what situation do you need to cast?
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    3. COThis is helpful. It's worth mentioning that the class _must_ come first, you cannot say '<T extends InterfaceB & ClassA>'.
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