Abstract: Mobile computing is gaining wide acceptance due to the rapid enhancement in wireless communications technologies. This has led to an increase in the demand for mobile information access. However, most mobile computing environment are very limited in resources, hence introducing new requirements and challenges for the software developer and engineer. To address these challenges applications has to be adaptive. In this paper, we describe mobile computing and its constraints. we describe adaptation spaces as a common framework for understanding the state-of-the-art in adaptive applications. A number of projects are reviewed and discussed. Then, a new rising paradigm in building adaptive applications is introduced based on component-based architecture. We believe this new approach will provide more flexible environment for building mobile applications.