void (@NotNull File dir) { LOG.debug("addLibraries: " + dir.getAbsolutePath() + ", exists: " + dir.exists()); File[] subFiles = dir.listFiles(); if (subFiles == null) { LOG.warn("Can't list files in " + dir); return; } for (File file : subFiles) { if (file.isDirectory()) { addLibraries(file); } else if (file.getName().endsWith(".jar")) { addFile(file); } } }