Classpath resource within jar

Question

I have a project A, which contains some java files and a classpath resource R.txt. Within the project I use ClassLoader.getSystemResource(\"R.txt\"); to retrieve R.txt.

Answer 1

Use getResource instead of getSystemResource to use a resource specific to a given classloader instead of the system. For example, try any of the following:

URL resource = getClass().getClassLoader().getResource("R.txt");
URL resource = Foo.class.getClassLoader().getResource("R.txt");
URL resource = getClass().getResource("/R.txt");
URL resource = Foo.class.getResource("/R.txt");

Note the leading slash when calling Class.getResource instead of ClassLoader.getResource; Class.getResource is relative to the package containing the class unless you have a leading slash, whereas ClassLoader.getResource is always absolute.