How to Access Properties File Within Executable JAR

Question

I have a properties file stored within /resources folder in my java Project.

Here is my code:

String fileName = "config.properties";
            
try (InputStream input = Main.class.getClassLoader().getResourceAsStream(fileName)) {
     if (input == null) {
          System.out.println("Sorry, unable to find " + fileName);
          return properties;
     }
            
            
     properties = new Properties();
     properties.load(input);

when I run the code in my IDE it works as intended... but when I export the project as an "runnable Jar file" and run the application using: java -jar <nameOfJar>.jar

Here is the resource folder present in the JAR file:

Can someone please explain to me why I can't read/load the properties file when it's converted to an executable JAR? Am I using the wrong file name?

EDIT pom.xml screenshot:

Answer 1

Perhaps this method will help shed a little light:

/**
 * Text files loaded with this method will work either within the IDE or your 
 * distributive JAR file.<br><br>
 * 
 * This method requires the Resource folder to be named "resources" which also 
 * contains a sub-folder named "textfiles". This resource folder is to be located 
 * directly within the Project "src" folder, for example:<pre>
 * 
 *      ProjectDirectoryName
 *          bin
 *          build 
 *          lib
 *          dist
 *          src
 *              resources
 *                  images
 *                      myImage_1.png
 *                      myImage_2.jpg
 *                      myImage_3.gif
 *                  textfiles
 *                      data_1.txt
 *                      data_2.txt
 *                      data_3.txt
 *          test</pre><br>
 * 
 * @param filePath (String) Based on the example folder structure above this 
 * would be (as an example):<pre>
 * 
 *    <b>  "/resources/textfiles/data_2.txt"  </b></pre>
 * 
 * @return ({@code List<String>}) A List of String containing the file's content.
 */
public List<String> loadFileFromResources(String filePath) throws IOException {
    List<String> lines = new ArrayList<>();
    try (java.io.InputStream in = getClass().getResourceAsStream(filePath);
    java.io.BufferedReader reader = new java.io.BufferedReader(new java.io.InputStreamReader(in))) {
        String line;
        while ((line = reader.readLine()) != null) {
            lines.add(line);
        }
        reader.close();
    }
    return lines;
}