def monkeypatch_method_if_not_set(cls):
    def decorator(func):
        print '!!! patching %s with %s' % (cls, func.__name__)
        if not hasattr(cls, func.__name__):
            setattr(cls, func.__name__, func)
        return func
    return decorator

from rpyc.core.netref import builtin_classes_cache
netref_list = builtin_classes_cache[('list', '__builtin__')]
print 'got', netref_list

@monkeypatch_method_if_not_set(netref_list)
def __tojava__(self, java_type):
    print '__tojava__ on', type(self)
    # from PySequence.java in Jython's source code
    if java_type.isArray():
        component = java_type.getComponentType()
        print '... got component as', type(component), repr(component)
        import array
        return array.array(component, self)
    UHOH