static File javaxArtifactsDir_dir; // can be set to work on different base dir

static File javaxArtifactsDir() {
  ret javaxArtifactsDir_dir != null ? javaxArtifactsDir_dir : new File(userHome(), "JavaX-Artifacts");
}

static File javaxArtifactsDir(S... subs) {
  ret newFile(javaxArtifactsDir(), subs);
}