我完全卸载了 Java，如下所示这帖子。不幸的是，我无法再重新安装 Java。
要重新安装 Java，我运行了以下命令：
$ sudo apt install default-jre
当我尝试使用以下命令检查 Java 版本时
$ java -version
我得到以下输出：
Command 'java' not found, but can be installed with:
sudo apt install default-jre
sudo apt install openjdk-11-jre-headless
sudo apt install openjdk-8-jre-headless
但是，当（重新）运行的时候sudo apt install default-jre，我得到：
Reading package lists... Done
Building dependency tree
Reading state information... Done
default-jre is already the newest version (2:1.11-68ubuntu1~18.04.1).
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
任何有关如何在完全卸载后重新安装 Java 的帮助这个帖子？我已经阅读了互联网上的很多文章，但我无法解决这个问题。
命令的输出
$ apt list --installed | egrep 'jdk|jre'
结果是：
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
default-jdk/bionic-updates,bionic-security,now 2:1.11-68ubuntu1~18.04.1 amd64 [installed]
default-jdk-headless/bionic-updates,bionic-security,now 2:1.11-68ubuntu1~18.04.1 amd64 [installed,automatic]
default-jre/bionic-updates,bionic-security,now 2:1.11-68ubuntu1~18.04.1 amd64 [installed]
default-jre-headless/bionic-updates,bionic-security,now 2:1.11-68ubuntu1~18.04.1 amd64 [installed,automatic]
openjdk-11-jdk/bionic-updates,bionic-security,now 11.0.4+11-1ubuntu2~18.04.3 amd64 [installed]
openjdk-11-jdk-headless/bionic-updates,bionic-security,now 11.0.4+11-1ubuntu2~18.04.3 amd64 [installed,automatic]
openjdk-11-jre/bionic-updates,bionic-security,now 11.0.4+11-1ubuntu2~18.04.3 amd64 [installed,automatic]
openjdk-11-jre-headless/bionic-updates,bionic-security,now 11.0.4+11-1ubuntu2~18.04.3 amd64 [installed]
openjdk-8-jdk/bionic-updates,bionic-security,now 8u222-b10-1ubuntu1~18.04.1 amd64 [installed]
openjdk-8-jdk-headless/bionic-updates,bionic-security,now 8u222-b10-1ubuntu1~18.04.1 amd64 [installed]
openjdk-8-jre/bionic-updates,bionic-security,now 8u222-b10-1ubuntu1~18.04.1 amd64 [installed,automatic]
openjdk-8-jre-headless/bionic-updates,bionic-security,now 8u222-b10-1ubuntu1~18.04.1 amd64 [installed]
答案1
似乎按照这个答案，你删除了所有与 Java 相关的二进制文件，但实际上并没有删除 OpenJDK 包。你可以通过运行来重新安装它们
sudo apt install --reinstall default-jre default-jdk default-jre-headless default-jdk-headless openjdk-11-jdk openjdk-11-jdk-headless openjdk-11-jre openjdk-11-jre-headless openjdk-8-jdk openjdk-8-jdk-headless openjdk-8-jre openjdk-8-jre-headless