Java, with a history of approximately 30 years, continues to rank high in programming language popularity. Even in Silicon Valley, Java remains a leading player in fields requiring high reliability, such as finance and e-commerce. In Japan, many core systems of major companies utilize Java, and the demand for Java engineers is high in the job market. In this context, this book meticulously explains the knowledge necessary to become a top-class "professional" Java engineer, from basic to advanced and practical applications. ★A book that systematically teaches from the basics to the practical aspects of Java★ This book carefully explains basic grammar such as variables, control structures, and classes, as well as advanced techniques like inheritance, interfaces, Stream API, and exception handling. Furthermore, it comprehensively covers a wide range of topics, including multithreading, testing with JUnit, application development using Swing and Spring Boot, ChatGPT API integration, database operations, and blockchain construction, enabling you to acquire skills directly applicable to practical work. ★We also teach engineers' success strategies★ The columns introduce how to improve your skills as an engineer, key points for success, and how to interact with generative AI. The author, who started from a humanities background with a TOEIC score in the 300s, sends a heartfelt message of encouragement. ★Points and sample code are also abundant★ "Points" are included to provide plenty of information on code writing tips, essential knowledge, and what is needed in the development field. "Sample code" that allows you to learn while working with your hands is available as a purchase bonus for download. 【Recommended for】 ・Beginners who want to work as engineers from now on ・People who are developing in other languages but want to learn Java ・Intermediate users who want to relearn Java