title: What is Class<?> vc or JavaType valueType used for in the constructor of Jackson's StdDeserializer
body: <p>I am making a custom deserializer (extending <code>StdDeserializer</code>) using the <a href="https://fasterxml.github.io/jackson-databind/javadoc/2.3.0/com/fasterxml/jackson/databind/deser/std/StdDeserializer.html" rel="nofollow">Jackson JSON library</a> and I can't figure out what the purpose of the constructor parameters are. What is <code>Class&lt;?&gt;</code> or <code>JavaType valueType</code> used for by Jackson? Is it just because Java doesn't have reified generics and Jackson needs more information about the generic type you're making an instance of?</p>