Java – The path to the test resource on Windows in Java unit testing

I’m using this code to get the path to the test resource file in the test code:

Path target = Path.of(
    Thread.currentThread().getContextClassLoader()
      .getResource("target1").getFile()
);

This file is located at src/test/resources/target1 and is copied to target/test-classes/tartget1 at build time.

It works fine on Unix-like systems, but on Windows it throws an exception:

java.nio.file.InvalidPathException: Illegal char <:> at index 2: /D:/a/project-name/repo-name/target/test-classes/target1

Use stack traces (from CI machines):

at java.base/sun.nio.fs.WindowsPathParser.normalize(WindowsPathParser.java:182)
at java.base/sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:153)
at java.base/sun.nio.fs.WindowsPathParser.parse(WindowsPathParser.java:77)
at java.base/sun.nio.fs.WindowsPath.parse(WindowsPath.java:92)
at java.base/sun.nio.fs.WindowsFileSystem.getPath(WindowsFileSystem.java:229)
at java.base/java.nio.file.Path.of(Path.java:147)

What is the right way to get a Path in a platform-agnostic way? I want to use the same code for Unixes and Windows machines. (It’s hard to debug this issue for me because I don’t have Windows machines, only CI and Windows.) )

The following works on my Windows machine, and your example fails as expected:

try {
  Path target = Paths.get(Thread.currentThread().getContextClassLoader()
      .getResource(FILE).toURI());
  System.out.println(target);
} catch (URISyntaxException e) {
  e.printStackTrace();
}

I think this is because parsing URIs is different from parsing strings.