Using an External Jar file

Question

I was hoping my intro programming class would be easy, as I've done some C++ before, but go figure, it's not.
Although the language/concepts aren't to difficult to learn, it seems compiling programs is. For one program, I'm giving an external .jar file to use. I'm using crimson editor and I do have it setup with the jdk1.6.0. It compiles all my other programs besides this one (command line doesn't work either).
Essentially, I've created a project, I have an instantiable class, and an application class. I can call the instantiable class in the app class and creating/modifying objects works just fine. Then I have a .jar file added to the project that came from the class (supposed to be used for I/O, don't know why we can't just use the standard java classes, but oh well). anyways, when I try to call the methods in the .jar file I get the following error:
---------- Capture Output ----------
"C:\Program Files\Java\jdk1.6.0\bin\javac.exe" file.javafile.java:6: cannot find symbol
symbol : variable externalJar
location: class file
          int value = externalJar.getIntInput();
          ^
After doing some searching, I found that it might be due to the classpath. So I set the classpath to the directory.. no go. Then I set the classpath to the externalJar.jar file and I get the follow error:
---------- Capture Output ----------
"C:\Program Files\Java\jdk1.6.0\bin\javac.exe" -classpath C:\folder\externalJar.jar file.javaerror: error reading C:\folder\externalJar.jar; error in opening zip file
I'm at a loss. It works when I use Eclipse and I can just add the external jar file, but I don't want to use eclipse, it's slow and bulky. Any other solutions to this problem? Thanks.
E-Rod
*names were changed for a reason.. i already know i'm not misspelling anything                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   

Answer 1

The error about not being able to find the variable externalJar has nothing
to do with the classpath. It's just that your code in file.java refers to this variable,
but you have not declared it anywhere.
Variables within a class, the names of classes and the names of .jar files
which contain packages have nothing whatsoever to do with one another.
If you are using a variable externalJar intending it to reference your external jar
file in some way, then your file.java code is seriously wrong.
(Also, classes and their associated source files should begin with an
uppercase letter.)
Regarding your attempt to specify the classpath when you invoke the
compiler (always a good idea), I think you should also include the current
directory (if that is where file.java is). Like this:"C:\Program Files\Java\jdk1.6.0\bin\javac.exe" -classpath C:\folder\externalJar.jar;. file.javaThe "error opening zip file" thing is odd. Make sure you are
able to read it (permissions OK, no other process has it locked). And that
it's not corrupt (Did you create it? If so, rebuild it. If not, aquire another copy.)
Sorry for the generalities and guesswork, but without seeing any code and
without knowing your directory structure or the contents of this externalJar.jar
it's hard to do any more.