> What is the difference of this to doppio? A new approach from some of the doppio authors?

(I contribute to both Javapoly and Doppio)

Javapoly tries to make Doppio easier to use (in my subjective opinion):

* 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.