Java, declare variable with multiple interfaces?
<p>In Java, is it possible to declare a field/variable whose type is multiple interfaces? For example, I need to declare a <code>Map</code> that is also <code>Serializable</code>. I want to make sure the variable references a serializable map. The <code>Map</code> interface does not extend <code>Serializable</code>, but most of <code>Map</code>'s implementations are <code>Serializable</code>.</p>

<p>I'm pretty sure the answer is no.</p>

<p><strong>Follow up</strong>: I'm fully aware of creating a new interface that extends both <code>Map</code> and <code>Serializable</code>. This will not work as existing implementations (such as <code>HashMap</code>) do not implement my new interface.</p>
