Adding external .properties files to a MANIFEST classpath

Question

Hi all;
I want to package my application as an executable jar (let's call it app.jar), but leave the config (.properties) file outside of it, so it can easily be edited after deployment. The config file should be added to the classpath, so that it can be loaded with ClassLoader.getResourceAsStream().
However, even though I add the directory where the config file lives to the classpath in the manifest of app.jar, it is not found by getResourceAsStream(). But if I package the config file in a separate jar (config.jar), and adds config.jar to the classpath of app.jar's manifest, it works.
Could someone explain why the config file is not picked up when not in a jar?

Answer 1

This external classpath thing for jars is quite frustrating.
But actually you can reference external directory, it does not have be in the exact same folder as the jar.
Lets say in the folder you have:
app.jar
lib/WrapperFramework.jar
config/config.properties
You can load the properties from a folder by:
- in code, use "class.getResourceAsStream("/config.properties");", the initial "/" is important, otherwise some package string is prepended.
- in manifest, use "Class-Path: lib/WrapperFramework.jar config/", the last "/" is important, otherwise it doesnt work. Super confusing since "." works fine.
Note that the folder in classpath is considered to be relative to the folder in which the original jar file is located. Hence if you execute jar from a random folder, the classpath is not broken (that's fortunate).
Edited by: AJG on Nov 15, 2007 5:33 PM