우분투에 자바를 설치하는 방법

http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

sudo tar zxvf ./jdk-8u101-linux-x64.tar.gz -C /usr/java/jdk1.8.0_101

JAVA_HOME=/usr/java/jdk1.8.0_101
JRE_HOME=$JAVA_HOME/jre
JAVA_BIN=$JAVA_HOME/bin
CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/binexport JAVA_HOME JRE_HOME PATH CLASSPATH

退出后：
source ~/.bashrc

class hello
{    public static void main(String[] args)
    {
        System.out.print("Hello world!\n");
    }
}