命令行选项-Ubuntu

Command Line option - Ubuntu

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update

然后在终端机

sudo apt-get install oracle-java8-installer

如果系统上有多个Java安装，则可以选择要用作默认Java版本.为此，请执行以下命令.

When there are multiple Java installations on your System, the Java version to use as default can be chosen. To do this, execute the following command.

sudo update-alternatives --config java
sudo update-alternatives --config javac
sudo update-alternatives --config javaws

编辑-手动安装Java

Edit - Manual Java Installation

下载oracle jdk

Download oracle jdk

http://www.oracle.com/technetwork/java/javase/downloads/index.html

将zip压缩到所需的文件夹中

Extract zip into desired folder

 e.g  /usr/local/  after extract /usr/local/jdk1.8.0_65

设置

sudo update-alternatives --install  /usr/bin/java java /usr/local/jdk1.8.0_65/bin/java 1
sudo update-alternatives --install  /usr/bin/javac javac /usr/local/jdk1.8.0_65/bin/javac 1
sudo update-alternatives --install  /usr/bin/javaws javaws /usr/local/jdk1.8.0_65/bin/javaws 1

sudo update-alternatives --set  java /usr/local/jdk1.8.0_65/bin/java
sudo update-alternatives --set  javac /usr/local/jdk1.8.0_65/bin/javac
sudo update-alternatives --set  javaws /usr/local/jdk1.8.0_65/bin/javaws

为外部应用程序(例如Eclipse和Idea)编辑/etc/environment设置JAVA_HOME路径

Edit /etc/environment set JAVA_HOME path for external applications like Eclipse and Idea