org.netbeans.InvalidException: StandardModule:org.netbeans.modules.db jarFile: /usr/share/netbeans/10.0/ide/modules/org-netbeans-modules-db.jar: java.lang.UnsupportedClassVersionError: org/netbeans/lib/ddl/DBConnection has been compiled by a more recent version of the Java Runtime (class file version 55.0), this version of the Java Runtime only recognizes class file versions up to 52.0

意思就是使用的jdk版本太旧了，netbeans需要jdk11, 解决方案： 注释掉.bashrc中的JAVA_HOME 然后apt安装最新的openjdk-11-jdk即可

注意我的环境是ubuntu18.10,如果不是这个版本的linux,自己下载jdk11的包，然后在.bashrc中指向这个jdk11的包即可