Practical Java Programming for IoT, AI, and Blockchain

Preface

I had my first programming experience when I was studying at Jilin University of Technology, China, in the 1990s. At that time, we were using mainframe computers, as personal computers (PCs) were not available in China. A mainframe computer is just one computer sitting somewhere in a room, and we connected to it through text-mode dumb terminals. As we connected to the mainframe computer using a shared account, a lot of strange things could happen. The program you created early on could be deleted or modified by someone else later. Printing was also a nightmare. For example, when you were printing your Fortran code, halfway through another student might send a printing request. The printer would immediately stop printing your code and start to print the other student's code. When finished, the printer would come back to resume printing the rest of your code. What kind of logic is that? So every time we wanted to print, we would shout “I am printing!” and hope others would not start to print their code at the same time. The programming language we used was Fortran, short for “formula translation.” Fortran is primarily designed for scientific calculations, and it is a very powerful language, but the Go To statement drove me crazy. It makes the code very difficult to read.

Later, when IBM PCs started to become available, our university also bought some IBM PCs and built a dedicated two floor building to host these computers. Yes, you heard me, a whole building was dedicated ...