We recently developed "System on Mobile Devices"(SyD) middleware for rapidly developing and deploying collaborative distributed applications over a collection of autonomous web objects and data-stores, independent of the underlying device, data, or network. SyDListener is a key component of SyD middleware. SyDListener provides a set of interfaces and classes that allows distributed SyD-based application components to communicate seamlessly in mobile environments. SyDListener provides a uniform object view of the underlying server application and enables client applications to remotely invoke those methods using XML messages. SyDListener is implemented as a multi-threaded wrapper with simple persistence management and asynchronous invocation functionality for J2ME Mobile Information Device Profile (MIDP) on Connected Limited Device Configuration (CLDL) devices. We discuss the functionality, architecture, implementation, and performance of SyDListener. We believe it is the first comprehensive working prototype of its kind for Java enabled handhelds with a small footprint of 10 KB.