How to define a relative path in java

Try something like this

String filePath = new File("").getAbsolutePath();
filePath.concat("path to the property file");

So your new file points to the path where it is created, usually your project home folder.

As @cmc said,

    String basePath = new File("").getAbsolutePath();
    System.out.println(basePath);

    String path = new File("src/main/resources/conf.properties").getAbsolutePath();
    System.out.println(path);

Both give the same value.