UBUNTU完美安裝JDK7x8

安裝jdk7 in ubuntu :
http://www.webupd8.org/2012/01/install-oracle-java-jdk-7-in-ubuntu-via.html

1.添加源:
sudo add-apt-repository ppa:webupd8team/java
2.更新:
sudo apt-get update 
3.安裝
sudo apt-get install oracle-java7-installer

jave -version 

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安裝jdk8 in ubuntu 網站:
http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html

1.添加源:
sudo add-apt-repository ppa:webupd8team/java
2.更新:
sudo apt-get update 
3.安裝
sudo apt-get install oracle-java8-installer

jave -version 

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Switching between Oracle Java 8 and Java 7

Later on, if you want to switch Oracle Java 7, use the following command (make sure “oracle-java7-installer” package is installed):

sudo update-java-alternatives -s java-7-oracle

And, switch back to Oracle Java 8 using:

sudo update-java-alternatives -s java-8-oracle

If you get some warnings when running these two commands, ignore them.

jdk7-jdk8替換
http://www.webupd8.org/2012/09/install-oracle-java-8-in-ubuntu-via-ppa.html

jdk7,jdk8指南
http://www.webupd8.org/2014/04/oracle-java-installer-conflicting-with.html