手順 java のバージョンを切り替える $ sudo update-alternatives --config java There are 2 programs which provide 'java'. Selection Command ----------------------------------------------- * 1 /usr/lib/jvm/jre-1.7.0-openjdk.x86_64/bin/java + 2 /usr/lib/jvm/jre-1.8.0-openjdk.x86_64/bin/java Enter to keep the current selection[+], or type selection number: javac のバージョンを切り替える $ sudo update-alternatives --config javac