getResourceAsStream returns null

I'm loading a text file from within a package in a compiled JAR of my Java project. The relevant directory structure is as follows:

/src/initialization/Lifepaths.txt

My code loads a file by calling Class::getResourceAsStream to return a InputStream.

public class Lifepaths {
    public static void execute() {
        System.out.println(Lifepaths.class.getClass().
            getResourceAsStream("/initialization/Lifepaths.txt"));
    }

    private Lifepaths() {}

    //This is temporary; will eventually be called from outside
    public static void main(String[] args) {execute();}
}

The print out will always print null, no matter what I use. I'm not sure why the above wouldn't work, so I've also tried:

• "/src/initialization/Lifepaths.txt"
• "initialization/Lifepaths.txt"
• "Lifepaths.txt"

Neither of these work. I've read numerous questions so far on the topic, but none of them have been helpful - usually, they just say to load files using the root path, which I'm already doing. That, or just load the file from the current directory (just load filename), which I've also tried. The file is being compiled into the JAR in the appropriate location with the appropriate name.

How do I solve this?

Solution 1:

Lifepaths.class.getClass().getResourceAsStream(...) loads resources using system class loader, it obviously fails because it does not see your JARs

Lifepaths.class.getResourceAsStream(...) loads resources using the same class loader that loaded Lifepaths class and it should have access to resources in your JARs

Solution 2:

The rules are as follows:

1. check the location of the file you want to load inside the JAR (and thus also make sure it actually added to the JAR)
2. use either an absolute path: path starts at the root of the JAR
3. use an relative path: path starts at the package directory of the class you're calling getResource/ getResoucreAsStream

And try:

Lifepaths.class.getResourceAsStream("/initialization/Lifepaths.txt")

instead of

Lifepaths.class.getClass().getResourceAsStream("/initialization/Lifepaths.txt")

(not sure if it makes a difference, but the former will use the correct ClassLoader/ JAR, while I'm not sure with the latter)