进入系统环境变量
sudo gedit /etc/profile
# set java environment
export JAVA_HOME=/home/liwenjie/Software/jdk1.8.0_131
export JRE_HOME=${JAVA_HOME}/jre
export CLASSPATH=.:${JAVA_HOME}/lib:${JRE_HOME}/lib
export PATH=${JAVA_HOME}/bin:$PATH
原文：http://www.cnblogs.com/li-wen-jie/p/7142474.html