(There will be no rigid theoretical articles in this book. The sample programs of each pattern in the book are written in Java language, which can be directly run on the computer, so that readers can deeply understand and use them. Learning to design Pattern is not only for preparing for the future, but also for reviewing the programs you usually write from a new perspective and improving the reusability and extensibility of software. This is the true meaning of designing Pattern, and it is also the intention of combining theory with examples in this book.
Design Pattern: Use in Java Language. pdf)