title: What are alternatives to the Java VM?
body: <p>As Oracle sues Google over the Dalvik VM it becomes clear, that you cannot implement a Java VM without license from Oracle (EDIT: Matthew Flaschen points out, that the claims of Oracle may not be valid. Anyways we have currently a situation, where Oracle threats VM-implementations.). That may become the death for Open-Source-implementations of Java (like <a href="http://harmony.apache.org/" rel="nofollow noreferrer">Apache Harmony</a>).</p>
  
  <p>I don't want to discuss the impact or the legitimation of this lawsuit. but as a Java-programmer I want to take a deeper look into the alternatives, to be prepared for every case. As I see the creation of a compiler as a minor problem, my main interest are alternative VM-implementations, that serve a similar purpose as the JVM.</p>
  
  <p>The VM I'm looking for, should meet some conditions:</p>
  
  <ul>
  <li>free of patent-issues</li>
  <li>an Open-Source-implementation exists</li>
  <li>potential for optimizations/good performance</li>
  <li>platform independent (the VM can be ported to different platforms without bigger hurdles)</li>
  </ul>
  
  <p>Please add some recommendations for me.</p>