Install jdk 7 under Ubuntu

WebStorm is based on java, so to install Webstorm on Ubuntu, you must first install jdk. The installation steps are as follows:

1.  Add PPA

       Terminal code:

1. sudo add-apt-repository ppa:webupd8team/java  
2. sudo apt-get update 

2. Install oracle-java-installer

        Terminal code: 

1. //jdk7    
2. sudo apt-get install oracle-java7-installer 

 3. Set the system default jdk

       Terminal code:

1. //JDk7   
2. sudo update-java-alternatives -s java-7-oracle  

 4. Switch between jdk versions

      Terminal code:

1. //jdk8 switch to jdk7 (if you install it for the first time, you don't need to execute this command)   
2. sudo update-java-alternatives -s java-7-oracle 

5.jdk installed successfully

      Terminal code:

1. java -version
2. java version "1.7.0_80"
3. Java(TM) SE Runtime Environment (build 1.7.0_80-b15)
4. Java HotSpot(TM) 64-Bit Server VM (build 24.80-b11, mixed mode)
5. dell@dell-Inspiron-5439:~$