title: What can you not do on the Dalvik VM (Android's VM) that you can in Sun VM?
body: <p>I know that you can run almost all Java in <em>Dalvik's VM</em> that you can in <em>Java's VM</em> but the limitations are not very clear.  Has anyone run into any major stumbling blocks?  Any major libraries having trouble?  Any languages that compile to Java byte code (<strong>Scala</strong>, <strong>Jython</strong> etc...) not work as expected?  </p>