Ubuntu 14.04 jdk8 설치하기

$ cd /opt

$ sudo wget --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u20-b26/jdk-8u20-linux-x64.tar.gz"

$ sudo tar -zxvf jdk-8u20-linux-x64.tar.gz

$ sudo update-alternatives --install /usr/bin/java java /opt/jdk1.8.0_20/bin/java 2

$ sudo update-alternatives --config java

There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                            Priority   Status

------------------------------------------------------------

* 0            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1071      auto mode

  1            /opt/jdk1.8.0_20/bin/java                                 2         manual mode

  2            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java   1071      manual mode

Press enter to keep the current choice[*], or type selection number: 1

$ sudo update-alternatives --install /usr/bin/javac javac /opt/jdk1.8.0_20/bin/javac 2

$ sudo update-alternatives --config javac

$ sudo update-alternatives --install /usr/bin/jar jar /opt/jdk1.8.0_20/bin/jar 2

$ sudo update-alternatives --config jar

$ sudo vi .bashrc

export JAVA_HOME=/opt/jdk1.8.0_20

export JRE_HOME=/opt/jdk1.8.0_20/jre

export PATH=$PATH:/opt/jdk1.8.0_20/bin:/opt/jdk1.8.0_20/jre/bin

$ echo $JAVA_HOME

$ echo $JRE_HOME