Ubuntu 18.04
자바 설치
sudo apt install openjdk-8-jdk
package 못 찾을 경우
sudo apt update
환경변수 설정
자바 경로 확인
$ which java
/usr/bin/java
$ readlink -f /usr/bin/java
/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
profile 추가
sudo vim /etc/profile
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java
export PATH=$PATH:$JAVA_HOME/bin
export CLASSPATH=$JAVA_HOME/jre/lib:$JAVA_HOME/lib/tools.jar
환경변수 적용
source /etc/profile