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copied!<p>The reason for the first result is that the <code>getClass</code> method has the following signature in Java</p> <pre><code>public final Class<?> getClass() </code></pre> <p>which Scala inherits. While we know that if we call <code>getClass</code> on an reference of type T the signature could be</p> <pre><code>public final Class<? extends T> getClass() </code></pre> <p>the compiler does not. You could imagine some language extension to provide a special type that represents the static type of the receiver that would enable</p> <pre><code>public final Class<? extends Receiver> getClass() </code></pre> <p>or some sort of special casing in the compiler for <code>getClass</code>. It seems in fact that Snoracle Java indeed special cases <code>getClass</code> but I'm not sure it's required by the Java Language Specification. However, if you have a reference of some particular static type T, there's no reason you couldn't do the equivalent <code>T.class</code> (java) or <code>classOf[T]</code> (scala). In other words such an extension would not bring any greater expressive power but would complicate the implementation of the language.</p> <p>As for the "compile time cast" versus the "'static' cast", there's really no difference there. It would be correct for a compiler to desugar <code>x.asInstanceOf[T]</code> to <code>classOf[T].cast(x)</code>.</p> <p>Any language with subtyping is going to have a possibility that the statically known type of a reference is less specific than the type of the value to which it refers. Languages with static type systems that do not have subtyping usually do not have a concept of runtime types as there is only one actual type that inhabits a given type name. In these languages types are erased at runtime, much the same way that type parameters are erased on the JVM.</p> <p>I hope this helps your understanding of static types of references as compared to runtime type of values.</p>

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