Fedora安装Oracle JDK

1. 下载Oracle JDK的tar.gz
2. sudo mkdir -p /usr/local/java
3. sudo cp -r jdk.*.tar.gz /usr/local/java
4. sudo tar xvzf jdk-8u45-linux-x64.tar.gz
5. 修改PATH（/etc/profile）
   sudo nano /etc/profile and paste the following at the end of the file:

JAVA_HOME=/usr/local/java/jdk1.8.0_45
PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
export JAVA_HOME
export PATH

6. 向系统声明新Oracle JDK可用：

   1. sudo update-alternatives --install "/usr/bin/java" "java" "/usr/local/java/jdk1.8.0_45/bin/java" 1
   2. sudo update-alternatives --install "/usr/bin/javac" "javac" "/usr/local/java/jdk1.8.0_45/bin/javac" 1
   3. sudo update-alternatives --install "/usr/bin/javaws.itweb" "javaws.itweb" "/usr/local/java/jdk1.8.0_45/bin/javaws.itweb" 1

7. 更改Oracle JDK为默认JDK：

   1. sudo update-alternatives --set java /usr/local/java/jdk1.8.0_45/bin/java
   2. sudo update-alternatives --set javac /usr/local/java/jdk1.8.0_45/bin/javac
   3. sudo update-alternatives --set javaws.itweb /usr/local/java/jdk1.8.0_45/bin/javaws.itweb

8. 使修改的/etc/profile生效：

   1. source /etc/profile

9. 重启