The object-oriented paradigmObject-oriented paradigm isObject-oriented software development, drawbackslearning the paradigm currently the most popular way of analyzing, designing, and developing application systems, especially large ones. To obtain an understanding of this paradigm, we could begin by asking: What exactly does the phrase “object-oriented” mean? Looking at it quite literally, labeling something as “object-oriented” implies that objects play a central role, and we elaborate this further as a perspective that views the elements of a given situation by decomposition into objects and object relationships. In a broad sense, this idea could apply to any setting, and examples of its application can, in fact, be found in business, chemistry, engineering, and even philosophy. Our business is with creating software and therefore this book concentrates on the object-oriented analysis, design, and implementation of software systems. Our situations are therefore problems that are amenable to software solutions, and the software systems that are created in response to these problems.