Using Threads in Java

One of the first software development contracts I had was to develop software for an invisible fence security system at thoroughbred horse farms in Kentucky, USA. The computer we used was an Apple II plus. There was no such thing as threads in the 6502 CPU or the OS, ProDOS. What we did was write all the code in assembly language in small units that were measured by the number of cycles each unit took. Once we finished our allotted cycles, we would save our state in a defined region of memory and turn over control to the next unit. It worked quite well, and if a horse wandered off, alarms would be sounded. The monitoring of the fence, just a buried cable that could detect a horse walking over it, continued even while the alarm sounded. This was my introduction to threaded programming. This was in 1982.

I did not work with threads again until 1999 when I moved from C++ to Java. One of the features that made Java stand out and why I abandoned C++ was Java’...