在全新的 Ubuntu 18.04 安装和 netbeans 安装之后，netbeans 不会启动。netbeans 已安装
sudo apt install netbeans
其他一些 Java 程序（至少是 Eclipse）也无法启动。
从命令行启动 netbeans 时，JVM 会打印以下警告：
? ~ netbeans
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.netbeans.ProxyURLStreamHandlerFactory (file:/usr/share/netbeans/platform18/lib/boot.jar) to field java.net.URL.handler
WARNING: Please consider reporting this to the maintainers of org.netbeans.ProxyURLStreamHandlerFactory
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
? ~