M-commerce has shown up as e-commerce in mobile and wireless communication, and now deals with on-line banking, stock trading, auctions, transactions, and mobile media. M-commerce applications are implemented with, for example, Java technology that supports a client-and-server model and cross-platform mobile applications. They are attractive, but, need a large heap space, which may slow down the execution, lead to poor interactive response, and sometimes cause out of memory¼¼ failure. We propose a Java computation mechanism with heap de/compression modules that reduce memory demand and allow client applications and embedded devices to take the advantage of compression techniques. Results show the impact in space and time efficiency of the proposed mechanism. The space effi