test/testlibrary/ClassFileInstaller.java

*** 43,53 ****
--- 43,55 ----
              String pathName = arg.replace('.', '/').concat(".class");
              InputStream is = cl.getResourceAsStream(pathName);
  
              // Create the class file's package directory
              Path p = Paths.get(pathName);
+             if (pathName.contains("/")) {
                  Files.createDirectories(p.getParent());
+             }
              // Create the class file
              Files.copy(is, p, StandardCopyOption.REPLACE_EXISTING);
          }
      }
  }