check path and classpath for duplicates

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

I do contract work for a living, which could include writing a program such as this. However, 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 endeavor.

Path Tool

This suggested student project is a tool that helps you deal with duplicates on the path and classpath. It also helps you find files that should be on the path or classpath but are not.

It displays the path and classpath with one element per line. It lists the jar names in the currently active ext directory, and the name of that directory. This is similar to the Which and What project.
I tell it someprog.exe then it tells me all the places on the path it found someprog.exe
I tell it someprog and it tells me all the places on the path it found someprog.exe, someprog.com, someprog.bat, and someprog.btm then tells me which one I would get.
I tell it com.mindprod.bulk.SomeClass.class It tells me all the places on the classpath (including the active ext jars) that it finds this class, and tells me which one java would actually use. The package name is optional.
I tell it com.mindprod.bulk.SomeClass.java It tells me all the places on the classpath (including src.zip) that it finds this class, and tells me which one javac would actually use. The package name is optional.
I ask it to search my entire hard disk and the contents of all jars and report as above.
You provide a text file containing a list of unqualified jar names you want available. The utility checks the classpath and reports any that don’t appear exactly once on the classpath.

Resources

Unix has a whence tool that handles searching the path, but not the classpath. According to Michael Amling, you can implement a crude version with Awk:

Most of what you need for a classpath search is implemented in ZipLock. See the storeClass(String className) method and the openResource(,) method it calls. You’d just need to modify main() to call openResource() and modify openResource(,) to print out the place where it found the .class file.

Eventually you might extend the ability of the program to search the entire Internet using jar catalog files and search engines. The other extension would be to deal in a similar way with DLL files (or equivalent) on the PATH.

Interface Finder: find classes on classpath implementing a given inteface
jar
jar verifier Project
JarCheck
JarLook
Java Jar Catalog Project
jcfind
Which and What Project: path and classpath analysis

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check path and classpath for duplicates

Path Tool

PathTool : Search Path and Classpath: Dummy Mockup

Resources