How to install the latest openjdk 12 on Ubuntu 18.04

Question

I've installed the default jdk by issuing the command:

apt-get install default-jdk

This will install openjdk 11 and apt-get seems to install the files all over the place. Examples:

/etc/java-11-openjdk/management
/usr/lib/jvm/java-11-openjdk-amd64/lib
/usr/share/doc/openjdk-11-jre-headless/JAVA_HOME
/var/lib/dpkg/info/openjdk-11-jre:amd64.postinst

As you can see by the example locations above, there are files scattered everywhere.

I've just installed a web app that's giving a warning that it only supports jdk 12 (I think it's the latest openjdk version). How can I install version 12 so that it replaces version 11? What is the best way to upgrade the openjdk version on Ubuntu 18.04 so that it doesn't mingle with the previous version?

Answer 1

这对我有用：

1. 使用wget下载档案或访问JDK 12 GA发行站点并手动下载档案：

wget https://download.java.net/java/GA/jdk12.0.2/e482c34c86bd4bf8b56c0b35558996b9/10/GPL/openjdk-12.0.2_linux-x64_bin.tar.gz

2. 创建/ usr / java目录：

sudo mkdir /usr/java

3. 将存档移到新目录：

mv openjdk-12.0.2_linux-x64_bin.tar.gz /usr/java

4. 转到此目录：

cd /usr/java

5. 解压缩档案：

sudo tar -xzvf openjdk-12.0.2_linux-x64_bin.tar.gz

6. 设置环境变量，为此打开/ etc / profile文件：

sudo nano /etc/profile

7. 并将以下代码添加到该文件的末尾：

JAVA_HOME=/usr/java/jdk-12.0.2
PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
export JAVA_HOME
export JRE_HOME
export PATH

8. 配置Java命令以默认使用新的JDK：

sudo update-alternatives --install "/usr/bin/java" "java" "/usr/java/jdk-12.0.2/bin/java" 1
sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/java/jdk-12.0.2/bin/javac" 1

9. 检查Java版本：

java --version

如果以前安装了其他版本的Java，但该版本未更改，请尝试运行以下命令并选择所需的版本：

sudo update-alternatives --config java

Answer 2

Ubuntu 的官方软件包存储库不提供 Openjdk12 软件包，因为 openjdk11 是您的版本的 openjdk 软件包的最后一个版本。