This appendix explored several features of the JDK that are increasingly helpful as you develop more experience with Java:

  • Using the Java debugger with applets and apps
  • Creating an optimized version of a compiled class
  • Writing applet methods that provide information to a browser upon request
  • Using the Java documentation creation tool to describe a class, its methods, and other aspects of the program fully

These JDK features weren't required during the 24 hours of this tutorial because of the relative simplicity of the tutorial programs. Although it can be complicated to develop a Swing app or to work with threads and streams for the first time, your biggest challenge lies ahead: integrating concepts such as these into more sophisticated Java programs. Tools such as javadoc and the debugger really come into their own on complex projects. When a bug occurs because of how two classes interact with each other, or similar subtle logic errors creep into your code, a debugger is the best way to identify and repair the problems. As you create an entire library of classes, javadoc can easily document these classes and show how they are interrelated.