Class getResourceAsStream() resource in a different package
classloader, eclipse, java
Solution
After many tries, the solution comes down to this little javadoc entry for `ClassLoader#getResource(String)`:
The name of a resource is a '/'-separated path name that identifies the resource.
The snippet I had originally posted would've worked
Utility.class.getResourceAsStream("/configuration_files/configuration_report.txt");
but I wasn't using `/`, I was using `File.separator` like in my edit:
String sourceFilePath = "/configuration_files" + File.separator + "configuration_report.txt";
thinking the class loader worked like OS specific File operations. The first `/` was matched, but the `File.separator` evaluated to `\\` since I'm on Windows.
The javadoc for `Class#getResource(String)` says more of the same.
Where the modified_package_name is the package name of this object with '/' substituted for '.' ('\u002e').
As to why this worked on Eclipse, but not from the command line, I'm still unsure, but look at @andy's comment below.
This article gives is a good explanation of this situation.
Problem
I have something like the following project structure ``` -project -src/main/java // source folder -com.mypackage -Utility.java -some.properties -src/main/resources // source folder -configuration_files -configuration_report.txt ``` I'm generating the `jar` with Eclipse's `Export` function. The above translates to a `jar` with the structure: ``` -myjar.jar -com -mypackage -Utility.class -some.properties -configuration_files -configuration_report.txt ``` Within the `Utility` class, I'm trying to get the `InputStream` from `configuration_report.txt`. I was doing this (it's within a `static` method): ``` Utility.class.getResourceAsStream("/configuration_files/configuration_report.txt"); ``` which seems to be validated by the answer to this question, since the file is not in the same package as the class requesting it. When I run it, however, it returns `null`. Why? Note that for the `some.properties` file, I could do both ``` Utility.class.getResourceAsStream("/com/package/some.properties"); Utility.class.getResourceAsStream("some.properties"); ``` and I would get the stream. I'm running this from the command line if it makes any difference. ``` java [-agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=1044] -cp myjar.jar MyMain ``` If I try to run it within Eclipse, it works... Edit: This code is relevant. With or without the preceding `/`, it return null ``` String sourceFilePath = "/configuration_files" + File.separator + "configuration_report.txt"; InputStream in = Utility.class.getResourceAsStream(sourceFilePath); ```