For the state of the art in object design, consider Patterns in Java, probably the best book they already have Java developers to get leading-edge pattern expertise in and comfortable well-organized volume. This guide opens with background on the study of patterns, including the groundbreaking Design Patterns. Next came the creation of patterns, such as Factory and Builder patterns and new patterns of Object Pool (which can be used to pool database connections for faster performance). After the switch to partition patterns, such as the Layered Initialization, and structural patterns, such as patterns Adapter, Facade, and flyweight. A part of the mix of old patterns of behavior patterns such as Chain of Responsibility and strategies with newer designs such as language and patterns of Little Snapshot.