the program javac can be found in the following packages ubuntu

在ubutnu 中安裝 oracle jdk　遇到了這個問題，閱讀以下兩篇文章：
http://www.wikihow.com/Install-Oracle-Java-JDK-on-Ubuntu-Linux
http://www.mkyong.com/java/how-to-install-oracle-jdk-8-on-debian/

主要是要解壓完成設置完路徑之後要記得設置：
sudo update-alternatives –install /usr/bin/java java /usr/local/java/jdk1.7.0_80/bin/java 100
sudo update-alternatives –install /usr/bin/javac javac /usr/local/java/jdk1.7.0_80/bin/javac 100