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Reimplement Standard Classes


This essay does not describe an existing computer program, just one that should exist. This essay is about a suggested student project in Java programming. This essay gives a rough overview of how it might work. I have no source, object, specifications, file layouts or anything else useful to implementing this project. Everything I have prepared to help you is right here.

This project outline is not like the artificial, tidy little problems you are spoon-fed in school, when all the facts you need are included, nothing extraneous is mentioned, the answer is fully specified, along with hints to nudge you toward a single expected canonical solution. This project is much more like the real world of messy problems where it is up to you to fully the define the end point, or a series of ever more difficult versions of this project and research the information yourself to solve them.

Everything I have to say to help you with this project is written below. I am not prepared to help you implement it; or give you any additional materials. I have too many other projects of my own.

Though I am a programmer by profession, I don’t do people’s homework for them. That just robs them of an education.

You have my full permission to implement this project in any way you please and to keep all the profits from your endeavour.

Please do not email me about this project without reading the disclaimer above.

This idea came from Mark Thornton. Reimplement java.lang.ThreadLocal so that synchronization only occurs when initially creating a value instance and when cleaning up old values (associated with dead threads).

Or more generally reimplement just about any standard class for greater efficiency, while, of course, retaining the same public interface. Try running a source code debugger tracing the actions of any standard class. Often the needless overhead will become clear. Profilers will also help.

Read the Bill Wilkinson Deja News posts from over the last year on the subject of serialization. Reimplement serialization in a way that would please Bill.

Devise a test suite to prove your classes behave the same as Oracle’s, or that clarify any deliberate differences and to benchmark performance. Post on and send copies to Sun.

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