Why Can't I access src/test/resources in Junit test run with Maven?

Question

I am having a problems running the following code:

configService.setMainConfig(\"src/test/resources/MainConfig.xml\");

From within a Junit @Bef

Answer 1

I ran into the same problem today and I have found some solutions.

First, here is my file structure:

.
└── src
│   └── test
│       ├── java
│       │   └── mypackage
│       │       └── MyClassTest.java
│       └── resources
│           └── image.jpg
└── target
    └── test-classes
            ├── image.jpg
            └── mypackage
                └── MyClassTest.class  

What is not working: (Java 11 synthax)

var imgFile = new File("image.jpg"); // I was expecting that Junit could find the file.
var absPath = file.getAbsolutePath(); // /home//..//image.jpg
var anyFileUnderThisPath = file.exists(); // false

What we can notice is that the absolute path does not point at all on my image! But if I had an image under at the project-root, then it would have worked.

Solution 1: Paths (introduced in Java 7)

var relPath = Paths.get("src", "test", "resources", "image.jpg"); // src/test/resources/image.jgp
var absPath = relPath.toFile().getAbsolutePath(); // /home//..//src/test/resources/image.jpg
var anyFileUnderThisPath = new File(absPath).exists(); // true

As we can see, it points on the right file.

Solution 2: ClassLoader

var classLoader = getClass().getClassLoader();
var url = classLoader.getResource("image.jpg"); // file:/home//..//target/test-classes/image.jpg
var file = new File(url.getFile()); // /home//..//target/test-classes/image.jpg
var anyFileUnderThisPath = file.exists(); // true

Note that now the file is searched under the target directory! and it works.

Solution 3: File (Adaptation of the non-working example)

var absPath = new File("src/test/resources/image.jpg").getAbsolutePath();
var var anyFileUnderThisPath = new File(absPath).exists(); // true

Which works also after taking the absolute path and putting src/test/resources/ as prefix.

Summary

All three solutions works but having to put src/test/resources/ is, in my own opinion not elegant, and this is why I would prefer the 2nd solution (ClassLoader).

Sources:

• Read file and resource in junit test
• Java read a file from resources folder