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Jar Verifier


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.

The jar.exe program is quite sloppy. It will let you create all manner of malformed jar files. What does it do?
  1. Make sure that every class file has a path that precisely matches its package name.
  2. Makes sure that the Manifest is present.
  3. Makes sure the manifest Main-Class Entry points to a valid class.main.
  4. Makes sure alls path entries are properly formed, e.g. no C:s in them and that all Class names begin with Capital letter.
  5. This is more difficult and could be left out on your first cut: check that all classes referenced, are included. Don’t stop on the first error. Give a full list of missing classes.
  6. An advanced version might prune classes that are not used, keeping a list of classes known to be dynmically loaded.
It might even correct type 1 errors which are so easy to make. It should not do it quietly because such errors imply there may be matching errors in resources that cannot be so easily detected.

Since I have been using GenJar much the urgency for this project has evaporated. It makes sure at least that all dependent classes are included, but not properties or dynamically loaded classes.

Interface Finder: find classes on classpath implementing a given inteface
Java Jar Catalog Project
Path and Classpath tool project
Which and What Project: path and classpath analysis

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