[Ubuntu][Linux] Can not execute the lately JAVA version that you've just installed.

We need to modify the setting, the command as below:

sudo update-alternatives --config java
sudo update-alternatives --config javac
(Modify both of them)

And you will see the selection list:

 Selection    Path                                         Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/java-7-openjdk-amd64/bin/javac   1051      auto mode
  1            /usr/lib/jvm/java-7-openjdk-amd64/bin/javac   1051      manual mode
  2            /usr/lib/jvm/jdk1.7.0_80/bin/jar              1         manual mode
  3            /usr/lib/jvm/jdk1.7.0_80/bin/java             1         manual mode
  4            /usr/lib/jvm/jdk1.7.0_80/bin/javac            1         manual mode
  5            /usr/lib/jvm/jdk1.7.0_80/bin/javadoc          1         manual mode

 Press enter to keep the current choice[*], or type selection number:


And then, you can update the version that you wanted.