Ubuntu15.04 Configure Java environment variables and install IntelliJ Idea__java

I. Configuration of JAVA environment variables
<1>. Download JDK
Download Address: (Please select the version number that suits your model)
Http://www.oracle.com/technetwork/cn/java/javase/downloads/jdk7-downloads-1880260.html
Note: To choose accept License Agreement, or not download.
<2> Decompression Installation
We install the JDK to this path:/USR/LIB/JVM.
If this directory is not found, a new directory is created.
Cd/usr/lib
sudo mkdir JVM
After we have created it, we will extract the JDK file/USR/LIB/JVM in the directory of the zipped package we just downloaded.
sudo tar-zxvf./jdk-8u45-linux-x64.tar.gz-c/USR/LIB/JVM
<3> Configure Environment variables
Vim/etc/profile
At the end of the open file, add:

Then enter the following command to make it effective:
Source/etc/profile
<4> Testing
Open the terminal and enter:
Java-version
Display results as:
Done!!!
two. Install IntelliJ idea
<1> Download IntelliJ Idea
Download Address: http://www.jetbrains.com/idea/download/
Decompression after download: TAR-ZXVF ideaic-14.1.3.tar.gz
Then run the software in the Unpacked Bin directory using the command sh idea.sh.
OK, now you can write a Java program!!!