问题
解决：
修改
/Applications/NetBeans/Apache NetBeans 12.0.app/Contents/Resources/NetBeans/netbeans/etc/netbeans.conf
设置
netbeans_jdkhome=”/Library/Java/JavaVirtualMachines/jdk-11.0.2.jdk/Contents/Home”
参考：
https://netbeans.org/community/releases/82/install.html