Java APIs

My program depends upon library classes written by someone else. These are distributed in a zip file containing only the .java files. I want to include that zip file in my javac sourcepath so that the classes will be compiled into the same place as the class files from the code I have written.

I'm using the command:

javac -d ../build -sourcepath .;..\lib\lib.zip mypackage\myclass.java

When executed I get an error for every one of the third party files saying "class x is public, should be declared in a file named x.java". It IS in a file named that, it's just that the file is inside a zip. The compiler is obviously finding the file.

Is this a limitation of javac? If so, it's not one that I can find any documentation for.

I know I can just unzip the thing, but I'm trying to put together an idiot-proof distribution and I'd like to include the 3rd-party stuff (which is open source) in exactly the format it's distributed in.