I'm tring to install jdk 8 for weeks, but it fails.Following are some outputs, sudo update-alternatives --config java There is only one alternative in link group java (providing /usr/bin/java): /opt/java-oracle/jdk1.8.0/bin/java Nothing to configure. which java /usr/bin/java java bash: /usr/local/java/jdk1.7.0_51/bin/java: No such file or directory ls -l /usr/bin/java /usr/bin/java -> /etc/alternatives/java ls -l /etc/alternatives/java /etc/alternatives/java -> /opt/java-oracle/jdk1.8.0/bin/java sudo update-alternatives --config javac /opt/java-oracle/jdk1.8.0/bin/javac 1 manual mode javac Error: could not find libjava.so Error: Could not find Java SE Runtime Environment. If you can please give me a help to slove this problem. Thank You