Trouble loading resources from inside JAR file...

Engines, Libraries and Tools Tools Discussion
#1

Hi there.

I am having some problems loading resources from within a jar file, and I don’t really know why…

Scenario: Project A (the “executable” project) uses project B ( lib project ).
Project B contains a class for loading resources.

It loads resources the typical way with MyClass.class.getClassLoader().getResource(…)

Now, while using Eclipse, this works great ( after setting some extra src folders. I have a src/bin setup for source files / compiled files ).

I did some basic tests, printing out various resource locations. For instance, take MyClass.class.getClassLoader().getResource(".");
In Eclipse, it rightly returns the folder from which Project A is launched. However, in the jar file, it returns null. In fact, everything I tried as a resource returned null.

Comparing the eclipse project files with the jar extracted confirms that the paths seem correct…

Anyone got an idea of what’s going on here?

#2

Yes, You cannot access files within a JAR using getResource(). You must use getResourceAsStream().

The reason it works in eclipse is because it executes it using class files not a JAR.

#3

You can, in fact, use getResource() from within a JAR file. What you can’t do is use getResource().getFile()

What you are facing may be related to the classloader. I would try getClass().getResource(…)

I just posted an example with source code last night of a JAR reading a file using getClass().getResource(…) … see if that works for you.

#4

Thanks, I got it working. I must have been very tired when I had the problem… Hehe. I was attempting to reach directories. Naturally this works well outside a jar, but not so well inside it, since the structure is flat. Oh well :slight_smile: It was a typical ‘DOH’ problem.