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The call to getResource could be done from the class that wants to know its location. It wouldn't need to be in a separate class.
If the class files are in a jarfile then there could be a problem.

What I meant to describe was how code in a class file would find the directory the class file is located in. I assumed that is what you were asking.
A combination of the path to the directory where...

For the java program to execute a class file, the file needs to be on the path referenced by the package/classpath.
If the java program uses a custom classloader then I imagine the class file could...