This work represents a detailed study of modular development approach, Java platform and the technologies accompanied by them. The motivation for this work is derived from the problem faced with developing complex systems and our love for developing Java applications. Modular development is a software development approach that emphasizes on dividing a software system into logically functional units (called modules) that can be assembled into a larger system. The software system developed to show the practical application of this approach is an intelligent system, which can be installed on PCs. Users will be granted different access rights to data according to their privilege where they will be allowed to Read, Modify or Delete certain data according to the users tasks or needs. This system will make dealing with sensitive and personal data a lot easier and more secure than it has ever been.