This book, through a large number of example programs, guides the readers to step by step grasp the basic skills of using Java development program. Consisting of 24 chapters totally, the book firstly introduces the writing process and working principles of Java program. Then, it introduces the basic knowledge of Java programming, including variables, conditional statements, Do statement, arrays and objects. Furthermore, it introduces the knowledge of graphical user interface creation, writing interactive Web applications, read and write files, and the use of use of fonts, colors and graphics. It also describes how to use Java to develop Android app.