In src/macosx/classes/java/util/prefs/MacOSXPreferences.java, the variable:

int componentCount = 0;

is not used:

    private MacOSXPreferencesFile cfFileForNode(boolean isUser)
    {
        String name = path;
        // /one/two/three/four/five/
        // The fourth slash is the end of the first three components.
        // If there is no fourth slash, the name has fewer than 3 components
        int componentCount = 0;
        int pos = -1;
        for (int i = 0; i < 4; i++) {
            pos = name.indexOf('/', pos+1);
            if (pos == -1) break;
        }

        if (pos == -1) {
            // fewer than three components - use default name
            name = defaultAppName;
        } else {
            // truncate to three components, no leading or trailing '/'
            // replace '/' with '.' to make filesystem happy
            // convert to all lowercase to survive on HFS+
            name = name.substring(1, pos);
            name = name.replace('/', '.');
            name = name.toLowerCase();
        }

        return MacOSXPreferencesFile.getFile(name, isUser);
    }