&gt; What is the difference of this to doppio? A new approach from some of the doppio authors?<p>(I contribute to both Javapoly and Doppio)<p>Javapoly tries to make Doppio easier to use (in my subjective opinion):<p>* easier loading of jars, classes and Java source code
* a promise based async interface to Java methods
* automatic marshaling of primitive values between JS and Java lands
* a proxy based interface into the Java namespace.